Convert USB fastboot code to use shared fastboot protocol.

Signed-off-by: Alex Kiernan <alex.kiernan@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

Merge UDP fastboot support from AOSP:

  https://android.googlesource.com/platform/external/u-boot/+/android-o-mr1-iot-preview-8

Signed-off-by: Alex Kiernan <alex.kiernan@gmail.com>
Signed-off-by: Alex Deymo <deymo@google.com>
Signed-off-by: Jocelyn Bohr <bohr@google.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

Ensure that when selecting FASTBOOT_FLASH you end up with a buildable
configuration. Prior to this you could select NAND without MTDPARTS
and end up with an image which (surprisingly) excluded NAND.

Also fix dependencies on FASTBOOT_GPT_NAME/FASTBOOT_MBR_NAME which require
you have EFI_PARTITION/DOS_PARTITION enabled.

Delete redundant FASTBOOT_FLASH_NAND_DEV from Kconfig - it was only ever
used as a guard and the value was ignored in all cases, we're using
FASTBOOT_FLASH_NAND as the guard now.

Signed-off-by: Alex Kiernan <alex.kiernan@gmail.com>
Reviewed-by: Joe Hershberger <joe.hershberger@ni.com>

Add drivers/fastboot/fb_common.c, where fastboot_okay/fail are implemented
so we can call them from a non-USB implementation.

Introduce fastboot_response which takes varargs parameters so we can
use it to generate formatted response strings. Refactor fastboot_okay/fail
to use it.

Signed-off-by: Alex Kiernan <alex.kiernan@gmail.com>
Reviewed-by: Joe Hershberger <joe.hershberger@ni.com>

Separate CMD_FASTBOOT from FASTBOOT and move code and configuration to
drivers/fastboot.

Switch dependencies on FASTBOOT to USB_FUNCTION_FASTBOOT as anyone who wants
FASTBOOT before this series wants USB_FUNCTION_FASTBOOT. Split
USB_FUNCTION_FASTBOOT from FASTBOOT so they retain their existing
behaviour.

Signed-off-by: Alex Kiernan <alex.kiernan@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>