Revert "sched, x86: Optimize branch hint in __switch_to()"

This reverts commit a3a1de0c.

Commit 8ec6993d cleared the es
and ds selectors, so the original branch hints are correct now.
Therefore the branch hint doesn't need to be removed.

Signed-off-by: Tim Blechmann <tim@klingt.org>
LKML-Reference: <4B16503A.8030508@klingt.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>