media: pxa_camera: Use fallthrough pseudo-keyword

In order to enable -Wimplicit-fallthrough for Clang[1], replace the
existing /* fall through  */ comments with the new pseudo-keyword
macro fallthrough[2].

[1] https://git.kernel.org/linus/e2079e93f562c7f7a030eb7642017ee5eabaaa10
[2] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-throughSigned-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/platform/pxa_camera.c

@@ -1256,7 +1256,7 @@ static void pxa_camera_setup_cicr(struct pxa_camera_dev *pcdev,
 		 * transformation. Note that UYVY is the only format that
 		 * should be used if pxa framebuffer Overlay2 is used.
 		 */
-		/* fall through */
+		fallthrough;
 	case V4L2_PIX_FMT_UYVY:
 	case V4L2_PIX_FMT_VYUY:
 	case V4L2_PIX_FMT_YUYV:
@@ -1667,7 +1667,7 @@ static int pxa_camera_get_formats(struct v4l2_device *v4l2_dev,
 				"Providing format %s using code %d\n",
 				pxa_camera_formats[0].name, code.code);
 		}
-	/* fall through */
+		fallthrough;
 	case MEDIA_BUS_FMT_VYUY8_2X8:
 	case MEDIA_BUS_FMT_YUYV8_2X8:
 	case MEDIA_BUS_FMT_YVYU8_2X8: