frv: Switch do_timer() to xtime_update()

__set_LEDS() does not need to be protected by xtime_lock.
its used unprotected in other places.

[ tglx: Removed stale comment ]

Signed-off-by: Torben Hohn <torbenh@gmx.de>
Cc: hch@infradead.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: johnstul@us.ibm.com
Cc: David Howells <dhowells@redhat.com>
Cc: yong.zhang0@gmail.com
LKML-Reference: <20110127145946.23248.57952.stgit@localhost>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>