This code is not LM4-specific, it's x86-specific. So it doesn't
belong in chip/lm4. Put it in its own module rather than leaving it
in switch.c, since some x86 systems may need the power button state
machine but not the backlight-enable passthru.
BUG=chrome-os-partner:18343
BRANCH=none
TEST=Quickly run a magnet over the lid switch; the backlight goes off and then
back on.
Change-Id: I72f7139b73f91539dcfbe6b5cb6d56587ab66fde
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/61595
Reviewed-by: Bill Richardson <wfrichar@chromium.org>
