media: v4l2-subdev.h: v4l2_subdev_call: use temp __sd variable

The sd argument of this macro can be a more complex expression. Since it
is used 5 times in the macro it can be evaluated that many times as well.

So assign it to a temp variable in the beginning and use that instead.

This also avoids any potential side-effects of evaluating sd.
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

include/media/v4l2-subdev.h

@@ -1093,13 +1093,14 @@ void v4l2_subdev_init(struct v4l2_subdev *sd,
  */
 #define v4l2_subdev_call(sd, o, f, args...)				\
 	({								\
+		struct v4l2_subdev *__sd = (sd);			\
 		int __result;						\
-		if (!(sd))						\
+		if (!__sd)						\
 			__result = -ENODEV;				\
-		else if (!((sd)->ops->o && (sd)->ops->o->f))		\
+		else if (!(__sd->ops->o && __sd->ops->o->f))		\
 			__result = -ENOIOCTLCMD;			\
 		else							\
-			__result = (sd)->ops->o->f((sd), ##args);	\
+			__result = __sd->ops->o->f(__sd, ##args);	\
 		__result;						\
 	})