wifi: iwlwifi: mvm: combine condition/warning

WARN() returns the value of the condition, so it's
nicer to combine the warning and the if.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://msgid.link/20240205211151.44f63334760e.If0a2cf347a8676a3830c5c3183a257fe11f31419@changeid


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