commands: harmonize in-barebox documentation ...

This patch does probably too much, but it's hard (and very
cumbersome/time consuming) to break it out. What is does is this:

* each command has one short description, e.g. "list MUX configuration"
* made sure the short descriptions start lowercase
* each command has one usage. That string contains just the
  options, e.g. "[-npn]". It's not part of the long help text.
* that is, it doesn't say "[OPTIONS]" anymore, every usable option
  is listed by character in this (short) option string (the long
  description is in the long help text, as before)
* help texts have been reworked, to make them
  - sometimes smaller
  - sometimes describe the options better
  - more often present themselves in a nicer format
* all long help texts are now created with BUSYBOX_CMD_HELP_
  macros, no more 'static const __maybe_unused char cmd_foobar_help[]'
* made sure the long help texts starts uppercase
* because cmdtp->name and cmdtp->opts together provide the new usage,
  all "Usage: foobar" texts have been removed from the long help texts
* BUSYBOX_CMD_HELP_TEXT() provides the trailing newline by itself, this
  is nicer in the source code
* BUSYBOX_CMD_HELP_OPT() provides the trailing newline by itself
* made sure no line gets longer than 77 characters
* delibertely renamed cmdtp->usage, so that we can get compile-time
  errors (e.g. in out-of-tree modules that use register_command()
* the 'help' command can now always emit the usage, even without
  compiled long help texts
* 'help -v' gives a list of commands with their short description, this
  is similar like the old "help" command before my patchset
* 'help -a' gives out help of all commands

Signed-off-by: Holger Schurig <holgerschurig@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

commands: group 'help' output ...

The old output of "help" was just producing a long list, that usually
scrolled of the screen (even on a X11 terminal). This list is more
compact, and also sorted by groups.

The old output format (plus grouping) is now available with 'help -v'.

Example:

   Information commands:
     ?, devinfo, help, iomem, meminfo, version
   Boot commands:
     boot, bootm, go, loadb, loads, loadx, loady, saves, uimage
   ...

Signed-off-by: Holger Schurig <holgerschurig@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

of: make of_get_fixed_tree more universally usable ...

Currently the bootm code uses of_fix_tree to apply the fixups
to the devicetree given on the command line. This function assumes
that there is enough space for the fixups available. Also on ARM
we have to make sure the tree does not cross 1Mib boundaries.

This patch moves the space allocation and alignment ensurance
to of_get_fixed_tree and uses it in bootm. This is the first
step for making of_get_fixed_tree the single point of devicetree
handling in barebox.
of_get_fixed_tree now takes an argument of the input fdt. If it is
given, this one is used, otherwise an internal oftree is used which
will be created in subsequent patches.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

arm lib: Remove redundant boot usage info from boot[uz].c ...

There is no need to add the command name to the "usage" info when
defining a command.

Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

commands: remove struct command pointer from commands ...

This is unused in all commands and thus can be removed.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

ARM boot[zu]: return COMMAND_ERROR_USAGE instead of calling barebox_cmd_usage ...

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

ARM: call start_linux directly with initrd start/size and oftree ...

whoever calls this function is not necessarily aware of a struct
image_data, so remove the dependency from the function.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

ARM: move bootu code to its own file ...

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>