MAINTAINERS: add myself as arm perf reviewer

As suggested by Will Deacon, add myself as a reviewer of the ARM PMU
profiling and debugging code.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
diff --git a/MAINTAINERS b/MAINTAINERS
index c6d977d..8addb19 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -822,6 +822,7 @@
 
 ARM PMU PROFILING AND DEBUGGING
 M:	Will Deacon <will.deacon@arm.com>
+R:	Mark Rutland <mark.rutland@arm.com>
 S:	Maintained
 F:	arch/arm*/kernel/perf_*
 F:	arch/arm/oprofile/common.c