Revert "[mips] Fix assertion on i128 addition/subtraction on MIPS64"

This reverts commit r227003. Support for addition/subtraction and
various other operations for the i128 data type will be added in a
future commit based on the review D7143.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227082 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed