bus: ARM CCN: add PERF_EVENTS dependency

The CCN driver makes no sense without PERF_EVENTS, and trying to
build it when that option is disabled results in compile errors,
so it's best to just add a strong Kconfig dependency.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

drivers/bus/Kconfig

@@ -53,6 +53,7 @@ config ARM_CCI
 config ARM_CCN
 	bool "ARM CCN driver support"
 	depends on ARM || ARM64
+	depends on PERF_EVENTS
 	help
 	  PMU (perf) driver supporting the ARM CCN (Cache Coherent Network)
 	  interconnect.