wifi: ray_cs: remove one redundant del_timer

In ray_detach, it and its child function ray_release both call
del_timer(_sync) on the same timer.

Fix this by removing the del_timer_sync in the ray_detach, and revising
the del_timer to del_timer_sync.

Signed-off-by: Dongliang Mu <dzm91@hust.edu.cn>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230316133236.556198-2-dzm91@hust.edu.cn