[COMMON] g2d: fix spinlock lockup for fence

[COMMON] g2d: fix spinlock lockup for fence

CPU1					CPU2
						spin_lock_irqsave(task->fence_timeout_lock)

fence_signal_locked() /* called with fence->lock held */
g2d_fence_callback()
spin_lock_irqsave(task->fence_timeout_lock)
						g2d_fence_timeout_handler()
						fence_remove_callback()
						spin_lock_irqsave(fence->lock)

On the above condition, two spinlock are deadlocked.

So, move fence_remove_callback() from fence_timeout_lock section.

Change-Id: If023ac94c2130ec0320814f3f2dc638c0031e761
Signed-off-by: hyesoo.yu <hyesoo.yu@samsung.com>