wifi: iwlwifi: mvm: check if EMLSR is allowed before selecting links

Currenty iwl_mvm_mld_select_links() doesn't fully check that
EMLSR is allowed before selecting the 2 best links.
Although it will fail in ieee80211_set_active_links(), it is preferred
to avoid the redundent calculations.

Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Link: https://msgid.link/20240416134215.3578a93feb1a.I1cd91608bb73fbe19b8dfdf90e14ce40b98c3430@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>