mm: Support malloc_size function

and rename malloc_usable_size to malloc_size

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>

arch/xtensa/src/esp32/esp32_wifi_adapter.c

@@ -3674,7 +3674,7 @@ static void *esp_realloc_internal(void *ptr, size_t size)
           return NULL;
         }
 
-      old_size = malloc_usable_size(old_ptr);
+      old_size = malloc_size(old_ptr);
       DEBUGASSERT(old_size > 0);
       memcpy(new_ptr, old_ptr, MIN(old_size, size));
       kmm_free(old_ptr);