sh: Update shmin to reflect PIO dependency.

shmin uses __set_io_port_base() for legacy I/O mapping that ethernet and
other SuperI/O functions depend on. Ensure that PIO support is built in
until the board is updated for MMIO properly.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

diff --cc arch/sh/Kconfig
Simple merge