efi: add and use new efi_device_has_guid helper ...

We have at least two places where we check if a efidev has a particular
guid and a follow-up commit will introduce a third place.

So lets factor it out into a helper.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

efi: populate boot source instance ...

We already determine the boot source variable at core init level, but so
far we didn't populate the instance because the numbering of the block
devices isn't known that early. Introduce a helper to check if a block
device is the boot source and if it is, have the block device driver
populate the missing boot source instance.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

efi: cleanups ...

make local functions static and remove unused code

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

efi-block: detect when the block device is a USB Disk ...

use usbdisk as a basename

This will be usefull as example when we want to search for a usb disk for
failsafe update or install.

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

efi: move bus driver to driver/efi ...

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

efi: move block io driver to driver/block ...

so it can be reused on any ARCH

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