board: ge: bx50v3: rename detect_baseboard function

The detect_baseboard() function actually determines whether there is an
internal LCD panel or not.  Rename for clarity.

Signed-off-by: Ian Ray <ian.ray@ge.com>
Signed-off-by: Nandor Han <nandor.han@ge.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>