ip2: fix compiler warning on ip2main_pci_tbl

Annotate ip2main_pci_tbl as '__used' to fix following warning:

  CC      drivers/char/ip2/ip2main.o
drivers/char/ip2/ip2main.c:3227: warning: ‘ip2main_pci_tbl’ defined but not used
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Cc: "Michael H. Warfield" <mhw@wittsend.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/char/ip2/ip2main.c

@@ -3224,7 +3224,7 @@ ip2trace (unsigned short pn, unsigned char cat, unsigned char label, unsigned lo
 
 MODULE_LICENSE("GPL");
 
-static struct pci_device_id ip2main_pci_tbl[] __devinitdata = {
+static struct pci_device_id ip2main_pci_tbl[] __devinitdata __used = {
 	{ PCI_DEVICE(PCI_VENDOR_ID_COMPUTONE, PCI_DEVICE_ID_COMPUTONE_IP2EX) },
 	{ }
 };