Modify getState to prefer AKEY_STATE_DOWN and AKEY_STATE_UP over AKEY_STATE_UNKNOWN.

For the getState() routines that operate on multiple devices / mappers:
Return AKEY_STATE_DOWN (or AKEY_STATE_VIRTUAL) if any of the devices/mappers
have the key down.
Otherwise, return AKEY_STATE_UP if at least one device/mapper returns AKEY_STATE_UP.
Otherwise, return AKEY_STATE_UNKNOWN.

Change-Id: I45a1f83d751c3c0cbfcc744dd3d6f0137ec8e01a