wifi: iwlwifi: mvm: guard against invalid STA ID on removal

Guard against invalid station IDs in iwl_mvm_mld_rm_sta_id as that would
result in out-of-bounds array accesses. This prevents issues should the
driver get into a bad state during error handling.

Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://msgid.link/20240320232419.d523167bda9c.I1cffd86363805bf86a95d8bdfd4b438bb54baddc@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>