/*
* void _x86_memio_unmap(bus_space_tag bst, bus_space_handle bsh,
* bus_size_t size, bus_addr_t *adrp)
*
* This function unmaps memory- or io-space mapped by the function
* _x86_memio_map(). This function works nearly as same as
* x86_memio_unmap(), but this function does not ask kernel
* built-in extents and returns physical address of the bus space,
* for the convenience of the extra extent manager.
*/