iwlwifi: remove MODULE_VERSION

The module version "in-tree:" or "in-tree:d" is useless; there
should be better (functional) ways to detect whether debugging
is enabled and other than that the version says nothing.

Therefore remove the driver version completely.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>