iwlwifi: update 5150 API version to support new firmware

update API to support new numbering that is used for other newer devices.
5150 ucode has not been released yet, so the first released API will be v2.
For those who do have a v1 API the driver does have backward compatibility
support new value of REPLY_TX_POWER_DBM_CMD

Signed-off-by: Jay Sternberg <jay.e.sternberg@linux.intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>