wifi: mac80211: refactor ieee80211_select_link_key()

Simplify ieee80211_select_link_key(), no functional changes are made.

Signed-off-by: Mukesh Sisodiya <mukesh.sisodiya@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230604120651.a4e332755bb0.Iff4a2b6ed767b2a329c51c29bb597ece9ebe2af8@changeid


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