hwc: Add a bits per pixel function for RGB color space

Change-Id: I12d286ffe12c18bc9159a9bd1df65db43b63ac05
Signed-off-by: Tony Lofthouse <a0741364@ti.com>
(cherry picked from commit d98182ec972e6083daec80f2271d2678abcc7b28)
1 file changed