Rename X86insrtps to the proper instruction name.

Summary:
The INSERTPS pattern fragment was called insrtps (mising 'e'), which
would make it harder to grep for the patterns related to this instruction.
Renaming it to use the proper instruction name.

Reviewers: nadav

CC: llvm-commits

Differential Revision: http://reviews.llvm.org/D3443

llvm-svn: 206779