net: sfp: make sfp_bus_find_fwnode() take a const fwnode

sfp_bus_find_fwnode() does not write to the fwnode, so let's make it
const.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/sfp-bus.c

@@ -593,7 +593,7 @@ static void sfp_upstream_clear(struct sfp_bus *bus)
  *	- %-ENOMEM if we failed to allocate the bus.
  *	- an error from the upstream's connect_phy() method.
  */
-struct sfp_bus *sfp_bus_find_fwnode(struct fwnode_handle *fwnode)
+struct sfp_bus *sfp_bus_find_fwnode(const struct fwnode_handle *fwnode)
 {
 	struct fwnode_reference_args ref;
 	struct sfp_bus *bus;

include/linux/sfp.h

@@ -557,7 +557,7 @@ int sfp_get_module_eeprom_by_page(struct sfp_bus *bus,
 void sfp_upstream_start(struct sfp_bus *bus);
 void sfp_upstream_stop(struct sfp_bus *bus);
 void sfp_bus_put(struct sfp_bus *bus);
-struct sfp_bus *sfp_bus_find_fwnode(struct fwnode_handle *fwnode);
+struct sfp_bus *sfp_bus_find_fwnode(const struct fwnode_handle *fwnode);
 int sfp_bus_add_upstream(struct sfp_bus *bus, void *upstream,
 			 const struct sfp_upstream_ops *ops);
 void sfp_bus_del_upstream(struct sfp_bus *bus);
@@ -619,7 +619,8 @@ static inline void sfp_bus_put(struct sfp_bus *bus)
 {
 }
 
-static inline struct sfp_bus *sfp_bus_find_fwnode(struct fwnode_handle *fwnode)
+static inline struct sfp_bus *
+sfp_bus_find_fwnode(const struct fwnode_handle *fwnode)
 {
 	return NULL;
 }