[media] mtk-vcodec: avoid warnings because of empty macros

Remove those gcc warnings:

	drivers/media/platform/mtk-vcodec/mtk_vcodec_dec_pm.c: In function 'mtk_vcodec_dec_pw_on':
	drivers/media/platform/mtk-vcodec/mtk_vcodec_dec_pm.c:114:51: warning: suggest braces around empty body in an 'if' statement [-Wempty-body]
	   mtk_v4l2_err("pm_runtime_get_sync fail %d", ret);
	                                                   ^

By adding braces.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/platform/mtk-vcodec/mtk_vcodec_util.h

@@ -66,15 +66,15 @@ extern bool mtk_vcodec_dbg;
 
 #else
 
-#define mtk_v4l2_debug(level, fmt, args...)
-#define mtk_v4l2_err(fmt, args...)
-#define mtk_v4l2_debug_enter()
-#define mtk_v4l2_debug_leave()
-
-#define mtk_vcodec_debug(h, fmt, args...)
-#define mtk_vcodec_err(h, fmt, args...)
-#define mtk_vcodec_debug_enter(h)
-#define mtk_vcodec_debug_leave(h)
+#define mtk_v4l2_debug(level, fmt, args...) {}
+#define mtk_v4l2_err(fmt, args...) {}
+#define mtk_v4l2_debug_enter() {}
+#define mtk_v4l2_debug_leave() {}
+
+#define mtk_vcodec_debug(h, fmt, args...) {}
+#define mtk_vcodec_err(h, fmt, args...) {}
+#define mtk_vcodec_debug_enter(h) {}
+#define mtk_vcodec_debug_leave(h) {}
 
 #endif