Use setup_timer() instead of init_timer() to simplify the code.

Link: http://lkml.kernel.org/r/5e75bf07beb91e092d5aa36c36769949a480456a.1489060564.git.geliangtang@gmail.comSigned-off-by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>