Revert "R600: Add work-around for the CF stack entry HW bug"

This reverts commit 35b8331cad6eb512a2506adbc394201181da94ba.

The -debug-only flag for llc doesn't appear to be available in
all build configurations.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199845 91177308-0d34-0410-b5e6-96231b3b80d8