ARM: PCI: versatile: Fix PCI I/O

The versatile PCI controller code was confused between the
PCI I/O window (at 0x43000000) and the first PCI memory
window (at 0x44000000). Pass the correct base address to
pci_remap_io() so that PCI I/O accesses work.

Since the first PCI memory window isn't used at all (it's
an odd size), rename the associated variables and labels
so that it's clear that it isn't related to the I/O window.

This has been tested and confirmed to fix PCI I/O accesses
both on physical PB926+PCI backplane hardware and on QEMU.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Cc: stable@vger.kernel.org
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Kevin Hilman <khilman@linaro.org>