The mutex adf_ctl_lock is initialized statically. It is
unnecessary to initialize by mutex_init().

Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
Acked-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>