Revert "MIPS: LD/SD o32 macro GAS fix update"

This reverts commit 97475f8b42e83be2966aa2d70ab9c98477701c53 (lmo) /
82b89152 (kernel.org) [MIPS: LD/SD o32
macro GAS fix update].

Turns out this patch is producing many build errors with gcc 4.2.  Based
on further testing with a test case extracted from the build errors found
further build errors and suboptimal generation even in violation of the
"R" constraint.

To make matters worse, the binutils changes also don't work quite as
intended so revert this patch for now.