state: merge backend.c into state.c ...

The code in backend.c is too small to justify an extra file. Merge it
into state.c.

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

state: Drop backend as extra struct type ...

struct state_backend is embedded into struct state. This additional
indirection does not have any real gain. Drop it.

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

state: backend: remove len_hint argument from state_storage_read ...

The argument is 0 in the only caller, so remove the argument.

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

state: backend: remove .get_packed_len ...

.get_packed_len isn't implemented by any backend, so remove the
hook and its potential caller.

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

barebox-state: Sync pieces with barebox ...

dev_add_param_bool are no-ops, save_on_shutdown is irrelevant for the
userspace part. Sync with barebox as of v2017.03.0

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

state: don't keep pointers to device tree nodes ...

Caching pointers to device tree nodes or is not save. The barebox internal
device tree may be changed by loading a new device tree or through fixup
handlers. As a result, the node may be deleted and replaced with a new one.
Keep a copy of the full path instead and resolve the node as needed.

Signed-off-by: Michael Olbrich <m.olbrich@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: make locally used function static ...

state_set_dirty() is only used in one file, make it static.

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

state: Add state to state_variable ...

A state variable should know which state it belongs to. Add field
for it to struct state_variable.

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

state: copy backend of_path string ...

Caching pointers to device tree nodes or names is not safe. The barebox
internal device tree may be changed by loading a new device tree or through
fixup handlers. As a result, the string may be deleted.
Use local copies of the full path instead.

Signed-off-by: Michael Olbrich <m.olbrich@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Revert "barebox-state: Add force switch" ...

This reverts commit 89135e5.

barebox-state: Add force switch ...

The force switch allows to read from a state even when the
keystore blobs cannot be read.

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

Update barebox-state ...

Fixed direct bucket

Signed-off-by: Markus Pargmann <mpa@pengutronix.de>

barebox-state: Import updated state code ...

Signed-off-by: Markus Pargmann <mpa@pengutronix.de>