ARM: 7441/1: perf: return -EOPNOTSUPP if requested mode exclusion is unavailable

We currently return -EPERM if the user requests mode exclusion that is
not supported by the CPU. This looks pretty confusing from userspace
and is inconsistent with other architectures (ppc, x86).

This patch returns -EOPNOTSUPP instead.
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/kernel/perf_event.c

@@ -503,7 +503,7 @@ __hw_perf_event_init(struct perf_event *event)
 	     event_requires_mode_exclusion(&event->attr)) {
 		pr_debug("ARM performance counters do not support "
 			 "mode exclusion\n");
-		return -EPERM;
+		return -EOPNOTSUPP;
 	}
 
 	/*