Fix documentation of sysrq-q

I fell into the trap recently that it only dumps hrtimers instead of
all timers. Fix the documentation.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: torvalds@linux-foundation.org
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>