media: saa7134: use swap() to make code cleaner

Use the macro 'swap()' defined in 'include/linux/minmax.h' to avoid
opencoding it.
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: David Yang <davidcomponentone@gmail.com>
Signed-off-by: Yang Guang <yang.guang5@zte.com.cn>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

drivers/media/pci/saa7134/saa7134-video.c

@@ -823,7 +823,7 @@ static int buffer_activate(struct saa7134_dev *dev,
 {
 	struct saa7134_dmaqueue *dmaq = buf->vb2.vb2_buf.vb2_queue->drv_priv;
 	unsigned long base,control,bpl;
-	unsigned long bpl_uv,lines_uv,base2,base3,tmp; /* planar */
+	unsigned long bpl_uv, lines_uv, base2, base3; /* planar */
 
 	video_dbg("buffer_activate buf=%p\n", buf);
 	buf->top_seen = 0;
@@ -868,11 +868,8 @@ static int buffer_activate(struct saa7134_dev *dev,
 		lines_uv = dev->height >> dev->fmt->vshift;
 		base2    = base + bpl * dev->height;
 		base3    = base2 + bpl_uv * lines_uv;
-		if (dev->fmt->uvswap) {
-			tmp = base2;
-			base2 = base3;
-			base3 = tmp;
-		}
+		if (dev->fmt->uvswap)
+			swap(base2, base3);
 		video_dbg("uv: bpl=%ld lines=%ld base2/3=%ld/%ld\n",
 			bpl_uv,lines_uv,base2,base3);
 		if (V4L2_FIELD_HAS_BOTH(dev->field)) {