Revert "MIPS: Reland 21774: Generate KeyedLoadGeneric with Hydrogen"

This reverts commit r21784 as the original CL also got reverted.

BUG=
TBR=danno@chromium.org

Review URL: https://codereview.chromium.org/329973002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21794 ce2b1a6d-e550-0410-aec6-3dcde31c8c00