net: 8021q/bluetooth/bridge/can/ceph: Remove extern from function prototypes

There are a mix of function prototypes with and without extern
in the kernel sources.  Standardize on not using extern for
function prototypes.

Function prototypes don't need to be written with extern.
extern is assumed by the compiler.  Its use is as unnecessary as
using auto to declare automatic/local variables in a block.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ceph/auth_x.h

@@ -45,7 +45,7 @@ struct ceph_x_info {
 	struct ceph_x_authorizer auth_authorizer;
 };
 
-extern int ceph_x_init(struct ceph_auth_client *ac);
+int ceph_x_init(struct ceph_auth_client *ac);
 
 #endif