can: some fixes and cleanups to the initial device driver interface

This patch fixes a few errors sneaked into the initial version of the
device driver interface.

Signed-off-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c
index 52b0e7d..574daddc 100644
--- a/drivers/net/can/dev.c
+++ b/drivers/net/can/dev.c
@@ -477,7 +477,7 @@
 
 	return 0;
 }
-EXPORT_SYMBOL(open_candev);
+EXPORT_SYMBOL_GPL(open_candev);
 
 /*
  * Common close function for cleanup before the device gets closed.