[MIPS] signal32: reduce {setup,restore}_sigcontext32 sizes
[MIPS] signal32: reduce {setup,restore}_sigcontext32 sizes

This trivial changes should decrease a lot the size of these
2 functions.

Signed-off-by: Franck Bui-Huu <e8d36543077b1c46c7df30e40a2816bc8ffc51e1@gmail.com>
Signed-off-by: Ralf Baechle <92f48d309cda194c8eda36aa8f9ae28c488fa208@linux-mips.org>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas