video: fbdev: pm2fb: 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
11940 660 16 12616 3148 drivers/video/fbdev/pm2fb.o

File size after adding 'const':
text data bss dec hex filename
12068 532 16 12616 3148 drivers/video/fbdev/pm2fb.o

Signed-off-by: Arvind Yadav <[e-mail]>
Cc: Paul Mackerras <[e-mail]>
Cc: Benjamin Herrenschmidt <[e-mail]>
Cc: Antonino Daplas <[e-mail]>
Cc: Maik Broemme <[e-mail]>
Cc: Florian Tobias Schandinat <[e-mail]>
Signed-off-by: Bartlomiej Zolnierkiewicz <[e-mail]>

drivers/video/fbdev/pm2fb.c

···
 	framebuffer_release(info);
 }
 
-static struct pci_device_id pm2fb_id_table[] = {
+static const struct pci_device_id pm2fb_id_table[] = {
 	{ PCI_VENDOR_ID_TI, PCI_DEVICE_ID_TI_TVP4020,
 	  PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0 },
 	{ PCI_VENDOR_ID_3DLABS, PCI_DEVICE_ID_3DLABS_PERMEDIA2,