FASTBOOT: Allow 'fastboot oem setinfo' to set device serialno

Device serialno is stored in device_info partition like the
mac addresses but is special because fastboot reports it
via 'fastboot getvar serialno'.

Also fix an error reporting case for erase attempt
on device_info partition.

Change-Id: I6792f2a084277ac22795d7f7653aa8160b9d6bd1
Signed-off-by: Mike J. Chen <[email protected]>
2 files changed