staging: mt7621-pci: properly adjust base address for the IO window

staging: mt7621-pci: properly adjust base address for the IO window

The value to adjust in the bridge register RALINK_PCI_IOBASE must take into
account the raw value from DT, not only the translated linux port number.
As long as io_offset is zero, the two are the same, but if you were to use
multiple host bridge in the system, or pick a different bus address in DT,
you can have a nonzero io_offset. At this means to take into account the
bus address which is used to calculate this offset, substracting it from
the IO resource start address.

Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Link: https://lore.kernel.org/r/20210925203224.10419-7-sergio.paracuellos@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>