ARM: EXYNOS: drop "select HAVE_SCHED_CLOCK"

The Kconfig symbol HAVE_SCHED_CLOCK got removed in v3.4,
with commit 6905a658 ("ARM: Make the sched_clock
framework mandatory"). Drop the last two select statements
for that symbol too. They're useless now.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>