video: fbdev: matroxfb: 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
  19884	   3036	     96	  23016	   59e8	fbdev/matrox/matroxfb_base.o

File size after adding 'const':
   text	   data	    bss	    dec	    hex	filename
  20300	   2620	     96	  23016	   59e8	fbdev/matrox/matroxfb_base.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/matrox/matroxfb_base.c

@@ -1623,7 +1623,7 @@ static int initMatrox2(struct matrox_fb_info *minfo, struct board *b)
 	unsigned int memsize;
 	int err;
 
-	static struct pci_device_id intel_82437[] = {
+	static const struct pci_device_id intel_82437[] = {
 		{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82437) },
 		{ },
 	};
@@ -2116,7 +2116,7 @@ static void pci_remove_matrox(struct pci_dev* pdev) {
 	matroxfb_remove(minfo, 1);
 }
 
-static struct pci_device_id matroxfb_devices[] = {
+static const struct pci_device_id matroxfb_devices[] = {
 #ifdef CONFIG_FB_MATROX_MILLENIUM
 	{PCI_VENDOR_ID_MATROX,	PCI_DEVICE_ID_MATROX_MIL,
 		PCI_ANY_ID,	PCI_ANY_ID,	0, 0, 0},