Map reference remote control to a single key-layout file

For early prototypes of the reference remote control, the VID/PID is
reported as 248a/8266 instead of 0957/0001 due to corrupt memory.
Instead of having redundant *.kl files we map both to the same file.
Removed keyboard.characterMap from *.idc files because no *.kcm files are provided.

Test: Verified in code that idc kl-mapping is used
Bug: 173100313
Change-Id: Ie22711b8dae1f0d7489ac5591c503126318f6309