atm: solos-pci: make solos_bh() as static

sparse says:

drivers/atm/solos-pci.c:763:6: warning:
 symbol 'solos_bh' was not declared. Should it be static?
Signed-off-by: NDaeseok Youn <daeseok.youn@gmail.com>
Acked-by: NChas Williams <chas@cmf.nrl.navy.mil>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/atm/solos-pci.c

@@ -760,7 +760,7 @@ static irqreturn_t solos_irq(int irq, void *dev_id)
 	return IRQ_RETVAL(handled);
 }
 
-void solos_bh(unsigned long card_arg)
+static void solos_bh(unsigned long card_arg)
 {
 	struct solos_card *card = (void *)card_arg;
 	uint32_t card_flags;