clocksource: arm_arch_timer: Hide eventstream Kconfig on non-ARM

Pavel Machek reports that this config is exposed on x86 where the
ARM architected timers aren't even present. Make it depend on the
ARM architected timers being selected so that non-ARM builds
aren't asked about it.
Reported-by: Pavel Machek <pavel@ucw.cz>
Reviewed-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

drivers/clocksource/Kconfig

@@ -87,6 +87,7 @@ config ARM_ARCH_TIMER
 config ARM_ARCH_TIMER_EVTSTREAM
 	bool "Support for ARM architected timer event stream generation"
 	default y if ARM_ARCH_TIMER
+	depends on ARM_ARCH_TIMER
 	help
 	  This option enables support for event stream generation based on
 	  the ARM architected timer. It is used for waking up CPUs executing