Remove PWM module which is not being used in order to save flash
space.
BUG=chrome-os-partner:34489
BRANCH=samus
TEST=make -j buildall. view .map file and see we save ~760 bytes.
Change-Id: Id107fb402a60c5ac7510982f8ace6bad46fb14d0
Signed-off-by: Alec Berg <alecaberg@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/239912
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>