Update stdlib_hashmap_chaining.f90

Bug fix

Author: chuckyvt

src/stdlib_hashmap_chaining.f90

@@ -551,7 +551,7 @@ module subroutine map_chain_entry(map, key, other, conflict)
         character(*), parameter :: procedure = 'MAP_ENTRY'
 
         ! Check that map is initialized.  
-        if (.not. map % initialized) init_chaining_map( map )
+        if (.not. map % initialized) call init_chaining_map( map )
 
         hash_val = map % hasher( key )