configs: ge_bx50v3: automatic partition selection and video output failure message

configs: ge_bx50v3: automatic partition selection and video output failure message

The exact definition of a successful boot is defined by user-space.
Determine the boot partition automatically.  A partition is selected if
file `/boot/bootcause/firstboot' exists (meaning that the partition has
freshly installed software) OR if file `/boot/fitImage' exists.

When userspace determines that new software was successfully installed,
it must (1) delete `/boot/fitImage' on the _inactive_ partition and (2)
remove `/boot/bootcause/firstboot'.

Enable video, but do not display logos or other version information.
Silence kernel console logging by default.

Print a message to VGA screen in case of boot failure and reset bootcount
to allow the user to attempt boot again.

Signed-off-by: Ian Ray <ian.ray@ge.com>
Signed-off-by: Martyn Welch <martyn.welch@collabora.co.uk>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>