iwlagn: override 5300 EEPROM # of chains

At least EEPROM version 0x11A has the wrong
number of chains programmed into it for some
reason, so we need to override in the driver.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>