staging: dgnc: make dgnc_poll_lock static

There's no need for this spinlock to be global, so make it a static
variable.

Cc: Lidza Louina <lidza.louina@gmail.com>
Cc: Mark Hounschell <markh@compro.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/dgnc/dgnc_driver.c

@@ -23,7 +23,7 @@ MODULE_SUPPORTED_DEVICE("dgnc");
 static unsigned int dgnc_num_boards;
 struct dgnc_board		*dgnc_board[MAXBOARDS];
 DEFINE_SPINLOCK(dgnc_global_lock);
-DEFINE_SPINLOCK(dgnc_poll_lock); /* Poll scheduling lock */
+static DEFINE_SPINLOCK(dgnc_poll_lock); /* Poll scheduling lock */
 int			dgnc_poll_tick = 20;	/* Poll interval - 20 ms */
 
 static ulong		dgnc_poll_time; /* Time of next poll */

drivers/staging/dgnc/dgnc_driver.h

@@ -375,7 +375,6 @@ struct channel_t {
 extern uint		dgnc_major;		/* Our driver/mgmt major */
 extern int		dgnc_poll_tick;		/* Poll interval - 20 ms */
 extern spinlock_t	dgnc_global_lock;	/* Driver global spinlock */
-extern spinlock_t	dgnc_poll_lock;		/* Poll scheduling lock */
 extern struct dgnc_board *dgnc_board[MAXBOARDS];/* Array of boards */
 
 #endif	/* _DGNC_DRIVER_H */