Update the MIPS scheduler by removing stale arch_env uses.
Update the MIPS scheduler by removing stale arch_env uses.

[r22774]

MatzeB/libfirm,jonashaag/libfirm,davidgiven/libfirm,8l/libfirm,libfirm/libfirm,jonashaag/libfirm,davidgiven/libfirm,MatzeB/libfirm,killbug2004/libfirm,jonashaag/libfirm,davidgiven/libfirm,davidgiven/libfirm,davidgiven/libfirm,jonashaag/libfirm,jonashaag/libfirm,libfirm/libfirm,killbug2004/libfirm,8l/libfirm,MatzeB/libfirm,libfirm/libfirm,libfirm/libfirm,8l/libfirm,davidgiven/libfirm,killbug2004/libfirm,killbug2004/libfirm,libfirm/libfirm,8l/libfirm,8l/libfirm,MatzeB/libfirm,davidgiven/libfirm,killbug2004/libfirm,MatzeB/libfirm,killbug2004/libfirm,8l/libfirm,8l/libfirm,MatzeB/libfirm,killbug2004/libfirm,jonashaag/libfirm,jonashaag/libfirm,MatzeB/libfirm