video: fbdev: via: 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
   3856	    968	    128	   4952	   1358	video/fbdev/via/via-core.o

File size after adding 'const':
   text	   data	    bss	    dec	    hex	filename
   4304	    520	    128	   4952	   1358	video/fbdev/via/via-core.o
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: Maik Broemme <mbroemme@libmpq.org>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

drivers/video/fbdev/via/via-core.c

@@ -724,7 +724,7 @@ static void via_pci_remove(struct pci_dev *pdev)
 }
 
 
-static struct pci_device_id via_pci_table[] = {
+static const struct pci_device_id via_pci_table[] = {
 	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, UNICHROME_CLE266_DID),
 	  .driver_data = UNICHROME_CLE266 },
 	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, UNICHROME_K400_DID),