light: remove unused blue channel
light: remove unused blue channel

Blue channel is not used anywhere, so just remove it, this would avoid also
some warnings at compile time.

Signed-off-by: Rui Miguel Silva <eab7c2dd6895f7ab24d530a9fb98cb8616b95852@gmail.com>
Signed-off-by: Greg Kroah-Hartman <4645f7897fd33786a2ee1264d590b3c400559d85@linuxfoundation.org>

projectara/gbsim,gregkh/gbsim,gregkh/gbsim,projectara/gbsim