Split iwl_mvm_sta into general and link specific parts. As a first
step, all link dependent parameters reside in deflink.

The change was done mostly using the spatch below with some manual
adjustments.

@iwl_mvm_sta@
struct iwl_mvm_sta *s;
identifier var = {sta_id, lq_sta, avg_energy};
@@

(
  s->
-    var
+    deflink.var
)
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230328104948.34eace06d583.I1f8c5e919a71b21030460fbdd220d42401b688b1@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>