[mips] Put some MIPS-specific sections to separate segments

Three MIPS-specific sections `.reginfo`, `.MIPS.options`, and `.MIPS.abiflags`
are used by loader to read their contents and setup environment for running
a program. Loader looks up these data in the corresponding segments:
`PT_MIPS_REGINFO`, `PT_MIPS_OPTIONS`, and `PT_MIPS_ABIFLAGS` respectively.

This patch put these sections to separate segments like we do already
for ARM `SHT_ARM_EXIDX` section.

Differential Revision: http://reviews.llvm.org/D58381

llvm-svn: 354468