wifi: mac80211: fix potential deadlock in ieee80211_key_link()

Add the missing unlock before return in the error handling case.

Fixes: ccdde7c7 ("wifi: mac80211: properly implement MLO key handling")
Signed-off-by: Sun Ke <sunke32@huawei.com>
Link: https://lore.kernel.org/r/20220827022452.823381-1-sunke32@huawei.com


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