iwlwifi: add new pci id for 6x35 series

commit 20ecf9fd3bebc4147e2996c08a75d6f0229b90df upstream.

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>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>