staging: vc04_services: vchiq_mmal: Rename service_callback()

Rename the service_callback static function to mmal_service_callback()
since the function signature conflicts with:

extern int
service_callback(struct vchiq_instance *vchiq_instance, enum vchiq_reason reason,
                 struct vchiq_header *header, unsigned int handle, void *bulk_userdata);

in vc04_services/interface/vchiq_arm/vchiq_arm.h

In a subsequent patch, we will include vchiq_arm.h header to
mmal-vchiq.c, which will then complain of this conflict. Hence,
this patch is meant to handle the conflict beforehand.
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
Reviewed-by: Stefan Wahren <wahrenst@gmx.net>
Link: https://lore.kernel.org/r/20240412075743.60712-10-umang.jain@ideasonboard.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.c

@@ -548,7 +548,7 @@ static void bulk_abort_cb(struct vchiq_mmal_instance *instance,
 }
 
 /* incoming event service callback */
-static int service_callback(struct vchiq_instance *vchiq_instance,
+static int mmal_service_callback(struct vchiq_instance *vchiq_instance,
 				 enum vchiq_reason reason, struct vchiq_header *header,
 				 unsigned int handle, void *bulk_ctx)
 {
@@ -1862,7 +1862,7 @@ int vchiq_mmal_init(struct vchiq_mmal_instance **out_instance)
 		.version		= VC_MMAL_VER,
 		.version_min		= VC_MMAL_MIN_VER,
 		.fourcc			= VCHIQ_MAKE_FOURCC('m', 'm', 'a', 'l'),
-		.callback		= service_callback,
+		.callback		= mmal_service_callback,
 		.userdata		= NULL,
 	};