ARM: keystone: drop useless HAVE_SCHED_CLOCK

The Kconfig symbol HAVE_SCHED_CLOCK got removed in v3.4,
with commit 6905a658 ("ARM: Make the sched_clock
framework mandatory"). But a select statement for it popped up again
through commit 828989ad ("ARM: keystone: Add minimal TI Keystone
platform support"). Drop that statement, as it is useless.
Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
[santosh.shilimkar@ti.com: Minor edit in the subject]
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>

arch/arm/mach-keystone/Kconfig

@@ -7,7 +7,6 @@ config ARCH_KEYSTONE
 	select HAVE_SMP
 	select CLKSRC_MMIO
 	select GENERIC_CLOCKEVENTS
-	select HAVE_SCHED_CLOCK
 	select ARCH_WANT_OPTIONAL_GPIOLIB
 	select ARM_ERRATA_798181 if SMP
 	help