For making the same binary executable on different SoCs which have
different DRAM addresses we have to be independent of the compile
time link address.

This patch adds relocatable binary support for the ARM architecture.
With this two new functions are available. relocate_to_current_adr
will fixup the binary to continue executing from the current position.
relocate_to_adr will copy the binary to a given address, fixup the
binary and continue executing from there.

For the PBL and the real image relocatable support can be enabled
independently. This is done to (hopefully) better cope with setups
where the PBL runs from SRAM or ROM and the real binary does not.

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

With relocatable binaries the linker is not able to supply absolute
addresses. These only get available when the relocation function is
being run. Since for early initialization we need some variables
before relocation, we supply them relatively to some known address
in the binary. This means that the variables have to be converted
to absolute addresses during runtime.

This patch adds a C macro and an assembly macro to calculate the
variables during runtime.

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

This function returns the offset between the address barebox is linked at
and the address barebox is currently running at.

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