media: v4l: use WARN_ON(1) instead of __WARN()

__WARN() cannot be used in portable code, since it is only
available on some architectures and configurations:

drivers/media/platform/pxa_camera.c: In function 'pxa_mbus_config_compatible':
drivers/media/platform/pxa_camera.c:642:3: error: implicit declaration of function '__WARN'; did you mean '__WALL'? [-Werror=implicit-function-declaration]

The common way to express an unconditional warning is WARN_ON(1),
so let's use that here.

Fixes: 97bbdf02d905 ("media: v4l: Add support for CSI-1 and CCP2 busses")

Signed-off-by: Arnd Bergmann <[e-mail]>
Acked-by: Sakari Ailus <[e-mail]>
Acked-by: Pavel Machek <[e-mail]>
Signed-off-by: Hans Verkuil <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/platform/pxa_camera.c

···
 					     V4L2_MBUS_CSI2_CONTINUOUS_CLOCK);
 		return (!mipi_lanes || !mipi_clock) ? 0 : common_flags;
 	default:
-		__WARN();
+		WARN_ON(1);
 		return -EINVAL;
 	}
 	return 0;

drivers/media/platform/soc_camera/soc_mediabus.c

···
 					     V4L2_MBUS_CSI2_CONTINUOUS_CLOCK);
 		return (!mipi_lanes || !mipi_clock) ? 0 : common_flags;
 	default:
-		__WARN();
+		WARN_ON(1);
 		return -EINVAL;
 	}
 	return 0;