Merging r258606:

------------------------------------------------------------------------
r258606 | Matthew.Arsenault | 2016-01-22 21:32:14 -0800 (Fri, 22 Jan 2016) | 5 lines

AMDGPU: Remove Feature64BitPtr

This is a leftover from AMDIL that doesn't do anything
and doesn't belong here.

------------------------------------------------------------------------

llvm-svn: 271587