metag, perf: Use common PMU interrupt disabled code

Transition to using the new generic PERF_PMU_CAP_NO_INTERRUPT method for
failing a sampling event when no PMU interrupt is available.

Signed-off-by: Vince Weaver <vincent.weaver@maine.edu>
Acked-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linux-metag@vger.kernel.org
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1406150202050.16738@vincent-weaver-1.umelst.maine.edu


Signed-off-by: Ingo Molnar <mingo@kernel.org>