Since DRM_ROTATE is counter clockwise (which is compliant with Xrandr),
and HW rotation is clockwise, swapping 90/270 to work as expected from
userspace.

v2: Rebased
Suggested-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NSonika Jindal <sonika.jindal@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>