iwlwifi: move hw_params into priv

The hw_params are mostly values that are
derived from the actual hardware config.
As such, while it is possible that MVM
will require similar ones, it makes more
sense -- at least for now -- to put them
into the DVM struct.

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>