MDEV-30812 fixup: GCC 12.2.0 -Wmaybe-uninitialized

best_access_path(): Simplify the logic for computing fanout.
This fixes up commit 4329ec5d

sql/sql_select.cc

@@ -8531,9 +8531,10 @@ best_access_path(JOIN      *join,
       fanout= hash_join_fanout(join, s, remaining_tables, rnd_records,
                                hj_start_key, &stats_found);
       join_sel= 1.0; // Don't do the "10% heuristic"
+      if (stats_found)
+        goto fanout_computed;
     }
-    if (!stats_found)
-    {
+
     /*
       No OPTIMIZER_SWITCH_HASH_JOIN_CARDINALITY or no field statistics
       found.
@@ -8548,8 +8549,8 @@ best_access_path(JOIN      *join,
       rnd_records= use_found_constraint(rnd_records);
     fanout= rnd_records;
     join_sel= 0.1;
-    }
 
+  fanout_computed:
     tmp= s->quick ? s->quick->read_time : s->scan_time();
     double cmp_time= (s->records - rnd_records)/TIME_FOR_COMPARE;
     tmp= COST_ADD(tmp, cmp_time);