[TC] defxx: TURBOchannel support

This is a set of changes to add TURBOchannel support to the defxx driver.  As
at this point the EISA support in the driver has become the only not having
been converted to the driver model, I took the opportunity to convert it as
well.  Plus support for MMIO in addition to PIO operation as TURBOchannel
requires it anyway.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>