drm/vc4: Allow some more signals to be packed with uniform resets.

The intent was to make sure people don't sneak in a small immediate or
something to change the interpretation of the uniform update args, but
these signals are just fine.

Fixes a validation failure in the current X server on some Render
operation.

Signed-off-by: Eric Anholt <eric@anholt.net>
diff --git a/drivers/gpu/drm/vc4/vc4_validate_shaders.c b/drivers/gpu/drm/vc4/vc4_validate_shaders.c
index 46527e9..2543cf5 100644
--- a/drivers/gpu/drm/vc4/vc4_validate_shaders.c
+++ b/drivers/gpu/drm/vc4/vc4_validate_shaders.c
@@ -309,8 +309,14 @@
 	 * of uniforms on each side.  However, this scheme is easy to
 	 * validate so it's all we allow for now.
 	 */
-
-	if (QPU_GET_FIELD(inst, QPU_SIG) != QPU_SIG_NONE) {
+	switch (QPU_GET_FIELD(inst, QPU_SIG)) {
+	case QPU_SIG_NONE:
+	case QPU_SIG_SCOREBOARD_UNLOCK:
+	case QPU_SIG_COLOR_LOAD:
+	case QPU_SIG_LOAD_TMU0:
+	case QPU_SIG_LOAD_TMU1:
+		break;
+	default:
 		DRM_ERROR("uniforms address change must be "
 			  "normal math\n");
 		return false;