disp: msm: add support for no blend planes

Some of the features in the DPU hardware needs planes to be staged but
it should not be blended in the layer mixer. Change adds support for drm
driver client to set the blend type on the plane and updates driver code
to skip staging the plane.

Change-Id: I1e8c7f6ce5617820ea8b24419e0d4d27b481819b
Signed-off-by: Gopikrishnaiah Anandan <agopik@codeaurora.org>

msm/sde/sde_plane.c

@@ -3421,7 +3421,8 @@ static void _sde_plane_install_properties(struct drm_plane *plane,
 		{SDE_DRM_BLEND_OP_NOT_DEFINED,    "not_defined"},
 		{SDE_DRM_BLEND_OP_OPAQUE,         "opaque"},
 		{SDE_DRM_BLEND_OP_PREMULTIPLIED,  "premultiplied"},
-		{SDE_DRM_BLEND_OP_COVERAGE,       "coverage"}
+		{SDE_DRM_BLEND_OP_COVERAGE,       "coverage"},
+		{SDE_DRM_BLEND_OP_SKIP,           "skip_blending"},
 	};
 	static const struct drm_prop_enum_list e_src_config[] = {
 		{SDE_DRM_DEINTERLACE, "deinterlace"}