staging: bcm2835-camera: Drop PREVIEW_LAYER

This define is used only once. So drop the define and init the layer
directly.
Reviewed-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Link: https://lore.kernel.org/r/1585485901-10172-2-git-send-email-stefan.wahren@i2se.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c

@@ -668,7 +668,7 @@ static int set_overlay_params(struct bm2835_mmal_dev *dev,
 			MMAL_DISPLAY_SET_ALPHA |
 			MMAL_DISPLAY_SET_DEST_RECT |
 			MMAL_DISPLAY_SET_FULLSCREEN,
-		.layer = PREVIEW_LAYER,
+		.layer = 2,
 		.alpha = dev->overlay.global_alpha,
 		.fullscreen = 0,
 		.dest_rect = {

drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.h

@@ -30,8 +30,6 @@ enum {
 	CAM_PORT_COUNT
 };
 
-#define PREVIEW_LAYER      2
-
 extern int bcm2835_v4l2_debug;
 
 struct bm2835_mmal_dev {