iwlwifi: add new pci id for 6x35 series

some new thinkpad laptops use intel chip with new pci id need be added
lspci -vnn output:
 Network controller [0280]: Intel Corporation Centrino Advanced-N 6235
 [8086:088f] (rev 24)
 Subsystem: Intel Corporation Device [8086:5260]
Signed-off-by: Shuduo Sang <sangshuduo@gmail.com>
Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/iwlwifi/pcie/drv.c

@@ -241,6 +241,7 @@ static DEFINE_PCI_DEVICE_TABLE(iwl_hw_card_ids) = {
 	{IWL_PCI_DEVICE(0x088F, 0x4260, iwl6035_2agn_cfg)},
 	{IWL_PCI_DEVICE(0x088E, 0x4460, iwl6035_2agn_cfg)},
 	{IWL_PCI_DEVICE(0x088E, 0x4860, iwl6035_2agn_cfg)},
+	{IWL_PCI_DEVICE(0x088F, 0x5260, iwl6035_2agn_cfg)},
 
 /* 105 Series */
 	{IWL_PCI_DEVICE(0x0894, 0x0022, iwl105_bgn_cfg)},