fix alsa device name constraint struct allocation

The bug was present in the inital version of the code,
commit ebba58c8ee

There was no memory corruption because while
jack_driver_param_value_enum_t is smaller by 72 bytes than
jack_driver_param_constraint_desc_t, for enum constraints,
the last 240 (on 64bit) bytes are not used.

linux/alsa/JackAlsaDriver.cpp

@@ -543,7 +543,7 @@ fill_device(
 
     if (*constraint_ptr_ptr == NULL)
     {
-        *constraint_ptr_ptr = (jack_driver_param_constraint_desc_t *)calloc(1, sizeof(jack_driver_param_value_enum_t));
+        *constraint_ptr_ptr = (jack_driver_param_constraint_desc_t *)calloc(1, sizeof(jack_driver_param_constraint_desc_t));
         *array_size_ptr = 0;
     }