iwlwifi: fix n-band association problem

This patch enables the IWL4965_HT flag (n-band) in Kconfig.
Removed the "depends on n" from Kconfig for config IWL4965_HT

Signed-off-by: Abhijeet Kolekar <abhijeet.kolekar@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>