ARC: Add perf support for ARC700 cores

This adds basic perf support for ARC700 cores. Most PERF_COUNT_HW* events
are supported now.

Signed-off-by: Mischa Jonker <mjonker@synopsys.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

arch/arc/boot/dts/angel4.dts

@@ -67,5 +67,9 @@
 				reg = <1>;
 			};
 		};
+
+		arcpmu0: pmu {
+			compatible = "snps,arc700-pmu";
+		};
 	};
 };