sh: Properly wire up channel 2's I/O window on SH7786 PCIe.

An IORESOURCE_IO was missing here, which meant that we weren't properly
establishing the I/O window for this particular slot. With this
corrected, cards with I/O BARs have them actually assigned and
accessible.

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