[PATCH] Don't disable irqs in set_next_event and set_mode callbacks

[Russell King - ARM Linux]

On Mon, Sep 21, 2009 at 09:39:22AM +0200, Uwe Kleine-König wrote:
> These functions are called with irqs already off.
> 
> at91rm2000 had a WARN_ON_ONCE if irqs were enabled since Nov 2008 with
> noone reporting having hit it.

It might be useful to document these clockevent interfaces.  There's
at least a few ARM clockevent implementations which don't set the
periodic interval when set_next_event() is called - probably because
it wasn't realised that it was required.