atm: he: 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
  26514	    440	     48	  27002	   697a	drivers/atm/he.o

File size After adding 'const':
   text	   data	    bss	    dec	    hex	filename
  26578	    376	     48	  27002	   697a	drivers/atm/he.o
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/atm/he.c

@@ -2851,7 +2851,7 @@ MODULE_PARM_DESC(irq_coalesce, "use interrupt coalescing (default 1)");
 module_param(sdh, bool, 0);
 MODULE_PARM_DESC(sdh, "use SDH framing (default 0)");
 
-static struct pci_device_id he_pci_tbl[] = {
+static const struct pci_device_id he_pci_tbl[] = {
 	{ PCI_VDEVICE(FORE, PCI_DEVICE_ID_FORE_HE), 0 },
 	{ 0, }
 };