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/can/af_can.h

@@ -108,9 +108,9 @@ struct s_pstats {
 extern struct dev_rcv_lists can_rx_alldev_list;
 
 /* function prototypes for the CAN networklayer procfs (proc.c) */
-extern void can_init_proc(void);
-extern void can_remove_proc(void);
-extern void can_stat_update(unsigned long data);
+void can_init_proc(void);
+void can_remove_proc(void);
+void can_stat_update(unsigned long data);
 
 /* structures and variables from af_can.c needed in proc.c for reading */
 extern struct timer_list can_stattimer;    /* timer for statistics update */