i386: remove unnecessary code

Oleg Nesterov pointed out that the set_fs() calls in setup_frame()
and setup_rt_frame() were superfluous.

[ tglx: arch/x86 adaptation ]

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Chuck Ebbert <76306.1226@compuserve.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>