isdn: mISDN: hfcmulti: 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
  63450	   1536	   1492	  66478	  103ae	isdn/hardware/mISDN/hfcmulti.o

File size After adding 'const':
   text	   data	    bss	    dec	    hex	filename
  64698	    288	   1492	  66478	  103ae	isdn/hardware/mISDN/hfcmulti.o
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/isdn/hardware/mISDN/hfcmulti.c

@@ -5348,7 +5348,7 @@ static const struct hm_map hfcm_map[] = {
 
 #undef H
 #define H(x)	((unsigned long)&hfcm_map[x])
-static struct pci_device_id hfmultipci_ids[] = {
+static const struct pci_device_id hfmultipci_ids[] = {
 
 	/* Cards with HFC-4S Chip */
 	{ PCI_VENDOR_ID_CCD, PCI_DEVICE_ID_CCD_HFC4S, PCI_VENDOR_ID_CCD,