media: v4l2-fwnode: make v4l2_fwnode_endpoint_parse_csi1_bus static

This function is used only internally. So, make it static.
Shuts up this warning:

drivers/media/v4l2-core/v4l2-fwnode.c:153:6: warning: no previous prototype for 'v4l2_fwnode_endpoint_parse_csi1_bus' [-Wmissing-prototypes]
 void v4l2_fwnode_endpoint_parse_csi1_bus(struct fwnode_handle *fwnode,
      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/v4l2-core/v4l2-fwnode.c

@@ -150,9 +150,10 @@ static void v4l2_fwnode_endpoint_parse_parallel_bus(
 
 }
 
-void v4l2_fwnode_endpoint_parse_csi1_bus(struct fwnode_handle *fwnode,
-					 struct v4l2_fwnode_endpoint *vep,
-					 u32 bus_type)
+static void
+v4l2_fwnode_endpoint_parse_csi1_bus(struct fwnode_handle *fwnode,
+				    struct v4l2_fwnode_endpoint *vep,
+				    u32 bus_type)
 {
 	struct v4l2_fwnode_bus_mipi_csi1 *bus = &vep->bus.mipi_csi1;
 	u32 v;