[media] m5mols: potential uninitialized variable

Smatch complains that there are some paths where "status" isn't
initialized.  The code does assume that m5mols_read_u8() can fail so it
seems as if Smatch is correct.

Let's initialize it to REG_ISO_AUTO which is zero.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>