video: fbdev: imsttfb: 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
   6736	    856	      0	   7592	   1da8	drivers/video/fbdev/imsttfb.o

File size after adding 'const':
   text	   data	    bss	    dec	    hex	filename
   6832	    760	      0	   7592	   1da8	drivers/video/fbdev/imsttfb.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/imsttfb.c

@@ -1318,7 +1318,7 @@ imsttfb_ioctl(struct fb_info *info, u_int cmd, u_long arg)
 	}
 }
 
-static struct pci_device_id imsttfb_pci_tbl[] = {
+static const struct pci_device_id imsttfb_pci_tbl[] = {
 	{ PCI_VENDOR_ID_IMS, PCI_DEVICE_ID_IMS_TT128,
 	  PCI_ANY_ID, PCI_ANY_ID, 0, 0, IBM },
 	{ PCI_VENDOR_ID_IMS, PCI_DEVICE_ID_IMS_TT3D,