ARM: 7894/1: kconfig: select GENERIC_CLOCKEVENTS if HAVE_ARM_ARCH_TIMER

The ARM architected timer driver doesn't compile without
GENERIC_CLOCKEVENTS selected, so ensure that we select it when building
for a platform that has the timer.

Without this patch, mach-virt fails to build without something like
mach-vexpress also selected.
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/Kconfig

@@ -1496,6 +1496,7 @@ config HAVE_ARM_ARCH_TIMER
 	bool "Architected timer support"
 	depends on CPU_V7
 	select ARM_ARCH_TIMER
+	select GENERIC_CLOCKEVENTS
 	help
 	  This option enables support for the ARM architected timer