fs: efivars: implement write support ...

Implement the standard FS ops for writing/manipulating
efivars.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

efi: add Barebox GUID ...

A proper GUID is needed to namespace all sorts of
things, most prominently persistent variables.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

efi: add proper reset hook ...

This allows to actually reset the system from barebox
instead of dropping back into the EFI firmware.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

efi: add function to determine type of device path ...

Thanks to the wonders of UEFI we have to walk down the
device path all the way until we arrive at the device
we got this path from...

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

EFI: introduce efi_strguid to convert GUID to human readable names ...

use in devinfo Protocols

Tested today on qemu with all the GUID translated

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Add initial EFI architecture support ...

This adds support for running barebox in an EFI environment
on X86 PC hardware.

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

efi: Add more error codes ...

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

Move efi.h to include/ ...

With upcoming EFI payload support the efi.h file will diverge
from the kernel, so move it from include/linux/ to include/

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