ARM: EXYNOS4: Fix routing timer interrupt to offline CPU

The commit 5dfc54e087c15f823ee9b6541d2f0f314e69cbed
("ARM: GIC: avoid routing interrupts to offline CPUs")
prevents routing interrupts to offline CPUs. But in
case of timer on EXYNOS4, the irq_set_affinity() method
is called in percpu_timer_setup() before CPU1 becomes
online. So this patch fixes routing timer interrupt to
offline CPU.

Reported-by: Changhwan Youn <chaos.youn@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>