atm: firestream: constify pci_device_id.

pci_device_id are not supposed to change at runtime. All functions
working with pci_device_id provided by <linux/pci.h> work with
const pci_device_id. So mark the non-const structs as const.

File size before:
   text	   data	    bss	    dec	    hex	filename
  16884	    444	     28	  17356	   43cc	drivers/atm/firestream.o

File size After adding 'const':
   text	   data	    bss	    dec	    hex	filename
  16980	    348	     28	  17356	   43cc	drivers/atm/firestream.o

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/atm/firestream.c

@@ -2030,7 +2030,7 @@ static void firestream_remove_one(struct pci_dev *pdev)
 	func_exit ();
 }
 
-static struct pci_device_id firestream_pci_tbl[] = {
+static const struct pci_device_id firestream_pci_tbl[] = {
 	{ PCI_VDEVICE(FUJITSU_ME, PCI_DEVICE_ID_FUJITSU_FS50), FS_IS50},
 	{ PCI_VDEVICE(FUJITSU_ME, PCI_DEVICE_ID_FUJITSU_FS155), FS_IS155},
 	{ 0, }