can: dev: export can_get_state_str() function

The can_get_state_str() function is also relevant to the drivers. Export the
symbol and make it visible in the can/dev.h header.

Link: https://lore.kernel.org/r/20210119170355.12040-1-mailhol.vincent@wanadoo.frSigned-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/dev/dev.c

@@ -74,7 +74,7 @@ static int can_rx_state_to_frame(struct net_device *dev, enum can_state state)
 	}
 }
 
-static const char *can_get_state_str(const enum can_state state)
+const char *can_get_state_str(const enum can_state state)
 {
 	switch (state) {
 	case CAN_STATE_ERROR_ACTIVE:
@@ -95,6 +95,7 @@ static const char *can_get_state_str(const enum can_state state)
 
 	return "<unknown>";
 }
+EXPORT_SYMBOL_GPL(can_get_state_str);
 
 void can_change_state(struct net_device *dev, struct can_frame *cf,
 		      enum can_state tx_state, enum can_state rx_state)

include/linux/can/dev.h

@@ -123,6 +123,7 @@ void unregister_candev(struct net_device *dev);
 int can_restart_now(struct net_device *dev);
 void can_bus_off(struct net_device *dev);
 
+const char *can_get_state_str(const enum can_state state);
 void can_change_state(struct net_device *dev, struct can_frame *cf,
 		      enum can_state tx_state, enum can_state rx_state);