x86/step: Remove enable_single_step TIF_SINGLESTEP workaround

We not longer rely on TIF_SINGLESTEP to set TF, nor do we set
TIF_SINGLESTEP if SYSENTER happens with TF set.  Remove this
workaround.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
1 file changed