media: v4l2: fix uninitialized value tuner_status(CWE-457)

Declaring variable "tuner_status" without initializer.
Using uninitialized value "tuner_status" when calling
"*fe_tuner_ops->get_status".
(The function pointer resolves to "cx24113_get_status".)

Signed-off-by: Yan Lei <yan_lei@dahuatech.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>