audio: fix audio driver del_timer BUG_ON crash issue [1/1]

audio: fix audio driver del_timer BUG_ON crash issue  [1/1]

PD#SWPL-972

Problem:
    audio crash when ATV switch channel long time burning test

Solution:
    there is a risk to fetch the timer lock. when input stop, stop_timer
    will call del_timer, at the same time the function
    "aml_i2s_hrtimer_callback" is waiting for the timer lock,after
    stop_timer release the lock,"aml_i2s_hrtimer_callback" get the
    lock and call mod_timer again, which will set the timer to pending
    status. It will cause the next  "start input" stage,add_timer will
    trigger BUG_ON.Now we put the lock before the active status
    checking then we will not touch the timer.

Verify:
    Need burning test

Change-Id: I1fb66903a4d31e9491ac0533e477e1597575d4cf
Signed-off-by: Jian Xu <jian.xu@amlogic.com>