MIPS: Octeon: Changes to support readq()/writeq() usage.

MIPS: Octeon: Changes to support readq()/writeq() usage.

Update OCTEON port mangling code to support readq() and
writeq() functions to allow driver code to be more portable.
Updates also for word and long function pairs. We also
remove SWAP_IO_SPACE for OCTEON platforms as the function
macros are redundant with the new mangling code.

Signed-off-by: Steven J. Hill <steven.hill@cavium.com>
Acked-by: David Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13780/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>