drm/amd/display: Fix warning about uninitialized variable

Signed-off-by: NHarry Wentland <harry.wentland@amd.com>
Reviewed-by: NBhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Acked-by: NHarry Wentland <Harry.Wentland@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dce/dce_mem_input.c

@@ -361,7 +361,7 @@ static void program_grph_pixel_format(
 	enum surface_pixel_format format)
 {
 	uint32_t red_xbar = 0, blue_xbar = 0; /* no swap */
-	uint32_t grph_depth, grph_format;
+	uint32_t grph_depth = 0, grph_format = 0;
 	uint32_t sign = 0, floating = 0;
 
 	if (format == SURFACE_PIXEL_FORMAT_GRPH_ABGR8888 ||