mips: rlimit codes are not the same

The codes for get/setrlimit differ between linux target platforms.
This patch adds conversion.
This is important else programs (rsyslog, python, ...) can go into a
near infinite loop trying to close all the file descriptors from 0 to
-1.

Signed-off-by: Wesley W. Terpstra <terpstra@debian.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
