sched/x86: Fix typo in __switch_to() comments

sched/x86: Fix typo in __switch_to() comments

Fix obvious mistake: FS/GS should be DS/ES.

Signed-off-by: Chuck Ebbert <cebbert.lkml@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20151014143119.78858eeb@r5
Signed-off-by: Ingo Molnar <mingo@kernel.org>