wifi: iwlwifi: don't use an uninitialized variable

Don't use variable err uninitialized.
The reason for removing the check instead of initializing it
in the beginning of the function is because that way
static checkers will be able to catch issues if we do something
wrong in the future.

Fixes: bf976c81

 ("wifi: iwlwifi: mvm: implement link change ops")
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230830112059.431b01bd8779.I31fc4ab35f551b85a10f974a6b18fc30191e9c35@changeid


Signed-off-by: Johannes Berg <johannes.berg@intel.com>