+ MIPS: more peephole optimizations (basically updated to the state of SPARC peephole).

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@27990 3ad0048d-3df7-0310-abae-a5850022a9f2
+ MIPS: added some instructions.

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@27991 3ad0048d-3df7-0310-abae-a5850022a9f2