aboot: mdtp: add delay before MDTP PIN is compared

If the correct PIN was entered, the LK menu is displayed.
When there's no delay, the previous "OK" press in MDTP UI
is considered again, causing the LK menu to be stuck until
the user performs additional operations or reboots the device.

Change-Id: I9452a39f8ec4b9fdd8b7a549210ab22df15e3ca6
1 file changed