video: fbdev: nvidia: 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
  12149	    768	     36	  12953	   3299	video/fbdev/nvidia/nvidia.o

File size after adding 'const':
   text	   data	    bss	    dec	    hex	filename
  12213	    704	     36	  12953	   3299	video/fbdev/nvidia/nvidia.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/nvidia/nvidia.c

@@ -55,7 +55,7 @@
 /* HW cursor parameters */
 #define MAX_CURS		32
 
-static struct pci_device_id nvidiafb_pci_tbl[] = {
+static const struct pci_device_id nvidiafb_pci_tbl[] = {
 	{PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID,
 	 PCI_BASE_CLASS_DISPLAY << 16, 0xff0000, 0},
 	{ 0, }