exynos: Set CNTFRQ

Commit 73a1cb27 moved the check whether we should set the architected
timer frequency from CONFIG_SYS_CLK_FREQ to CONFIG_TIMER_CLK_FREQ, but
did not update all users of it.

The one where I (finally) realized why KVM didn't work is the Arndale
board, so this patch adds the respective define to it.

Signed-off-by: Alexander Graf <agraf@suse.de>
Fixes: 73a1cb27
Reviewed-by: York Sun <york.sun@nxp.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>