MIPS: MSP71xx: Resolve use of non-existent GPIO routines in msp71xx reset

There have been a number of compile problems with the msp71xx configuration
ever since it was included in the linux-mips.org repository.  This patch
resolves compilation problems with attempting to reset the board using
non-existent GPIO routines.

This patch has been compile-tested against the current HEAD.

Signed-off-by: Shane McDonald <mcdonald.shane@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>