[mips] Improve handling of -fno-[pic/PIC] option

In order to disable PIC and to match GCC behaviour, -mno-abicalls
option is neccessary. When -fno-[pic/PIC] is used witout -mno-abicalls,
warning is reported. An error is reported when -fno-pic or -fno-PIC is
used in combination with -mabicalls.

Depends on D44381.

Differential Revision: https://reviews.llvm.org/D44684

llvm-svn: 331636