gallium: add packed uniform CAP

Reviewed-by: Marek Olšák <marek.olsak@amd.com>

src/gallium/drivers/softpipe/sp_screen.c

@@ -313,6 +313,7 @@ softpipe_get_param(struct pipe_screen *screen, enum pipe_cap param)
    case PIPE_CAP_CONTEXT_PRIORITY_MASK:
    case PIPE_CAP_FENCE_SIGNAL:
    case PIPE_CAP_CONSTBUF0_FLAGS:
+   case PIPE_CAP_PACKED_UNIFORMS:
       return 0;
    case PIPE_CAP_SHADER_BUFFER_OFFSET_ALIGNMENT:
       return 4;