tty: serial: jsm: 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
   2442	   1088	      8	   3538	    dd2	tty/serial/jsm/jsm_driver.o

File size After adding 'const':
   text	   data	    bss	    dec	    hex	filename
   3082	    448	      8	   3538	    dd2 tty/serial/jsm/jsm_driver.o
Signed-off-by: NArvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/jsm/jsm_driver.c

@@ -304,7 +304,7 @@ static void jsm_remove_one(struct pci_dev *pdev)
 	kfree(brd);
 }
 
-static struct pci_device_id jsm_pci_tbl[] = {
+static const struct pci_device_id jsm_pci_tbl[] = {
 	{ PCI_DEVICE(PCI_VENDOR_ID_DIGI, PCI_DEVICE_ID_NEO_2DB9), 0, 0, 0 },
 	{ PCI_DEVICE(PCI_VENDOR_ID_DIGI, PCI_DEVICE_ID_NEO_2DB9PRI), 0, 0, 1 },
 	{ PCI_DEVICE(PCI_VENDOR_ID_DIGI, PCI_DEVICE_ID_NEO_2RJ45), 0, 0, 2 },