iwlwifi: driver version track kernel version

The driver version number is a remnant from when there was an out-of-tree
iwlwifi driver. Now that the driver forms part of kernel source we do not
need a separate driver version. Instead, we now use the kernel version as
driver version. We maintain the previous tags used to indicate which
components the driver has been compiled with.

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Acked-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>