display5: Support for the emergency PAD pressing

To enter the special mode, one needs to short cut two pads with e.g. screw
driver.

After power up the SPL will execute u-boot in which proper actions will be
taken.

It is worth noting that we do not alter envs (even the BOOT_FROM variable)
and unconditionally go to recovery.

Signed-off-by: Lukasz Majewski <lukma@denx.de>
5 files changed