bootstd: android: Allow boot with AVB failures when unlocked

bootstd: android: Allow boot with AVB failures when unlocked

When the bootloader is UNLOCKED, it should be possible to boot Android
even if AVB reports verification errors [1].

This allows developers to flash modified partitions on
userdebug/engineering builds.

Developers can do so on unlocked devices with:
$ fastboot flash --disable-verity --disable-verification vbmeta vbmeta.img

In such case, bootmeth_android refuses to boot.

Allow the boot to continue when the device is UNLOCKED and AVB reports
verification errors.

[1] https://source.android.com/docs/security/features/verifiedboot/boot-flow#unlocked-devices

Fixes: 125d9f3306ea ("bootstd: Add a bootmeth for Android")
Reviewed-by: Julien Masson <jmasson@baylibre.com>
Link: https://lore.kernel.org/r/20250108-avb-disable-verif-v2-2-ba7d3b0d5b6a@baylibre.com
Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>