media: firewire: Using uninitialized values in node_probe()

If fw_csr_string() returns -ENOENT, then "name" is uninitialized.  So
then the "strlen(model_names[i]) <= name_len" is true because strlen()
is unsigned and -ENOENT is type promoted to a very high positive value.
Then the "strncmp(name, model_names[i], name_len)" uses uninitialized
data because "name" is uninitialized.

Fixes: 92374e88

 ("[media] firedtv: drop obsolete backend abstraction")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>