Instead of reading out the register, use a cached value. This will
make way for a proper runtime power management implementation.
Signed-off-by: NBastian Hecht <hechtb@gmail.com>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>