drivers: CCI: fix used_mask init in validate_group()

Currently in validate_group(), there is a static initializer
for fake_pmu.used_mask which is based on CPU_BITS_NONE but
the used_mask array size is based on CCI_PMU_MAX_HW_EVENTS.
CCI_PMU_MAX_HW_EVENTS is not based on NR_CPUS, so CPU_BITS_NONE
is not correct and will cause a build failure if NR_CPUS
is set high enough to make CPU_BITS_NONE larger than used_mask.

Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Mark Salter <msalter@redhat.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

drivers/bus/arm-cci.c

@@ -660,7 +660,7 @@ validate_group(struct perf_event *event)
 		 * Initialise the fake PMU. We only need to populate the
 		 * used_mask for the purposes of validation.
 		 */
-		.used_mask = CPU_BITS_NONE,
+		.used_mask = { 0 },
 	};
 
 	if (!validate_event(event->pmu, &fake_pmu, leader))