drm: Add drm_rotation_90_or_270()

We have intel_rotation_90_or_270() in i915 to check if the rotation is
90 or 270 degrees. Similar checks are elsewhere in drm, so let's move
the helper into a central place and use it everwhere.

v2: Drop the BIT()
    Convert all new intel_rotation_90_or_270() calls
    Deal with superfluous code shuffling

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> (v1)
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1474907460-10717-2-git-send-email-ville.syrjala@linux.intel.com
diff --git a/drivers/gpu/drm/omapdrm/omap_plane.c b/drivers/gpu/drm/omapdrm/omap_plane.c
index 66ac8c4..1549e83 100644
--- a/drivers/gpu/drm/omapdrm/omap_plane.c
+++ b/drivers/gpu/drm/omapdrm/omap_plane.c
@@ -108,16 +108,12 @@
 	win.src_x = state->src_x >> 16;
 	win.src_y = state->src_y >> 16;
 
-	switch (state->rotation & DRM_ROTATE_MASK) {
-	case DRM_ROTATE_90:
-	case DRM_ROTATE_270:
+	if (drm_rotation_90_or_270(state->rotation)) {
 		win.src_w = state->src_h >> 16;
 		win.src_h = state->src_w >> 16;
-		break;
-	default:
+	} else {
 		win.src_w = state->src_w >> 16;
 		win.src_h = state->src_h >> 16;
-		break;
 	}
 
 	/* update scanout: */