MIPS: Remove arch specific api callback generate functions.

Port r19406 (4eab88a)

BUG=
R=gergely@homejinni.com

Review URL: https://codereview.chromium.org/169243003

Patch from Balazs Kilvady <kilvadyb@homejinni.com>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@19421 ce2b1a6d-e550-0410-aec6-3dcde31c8c00