vfio/mdev: remove unnecessary NULL check in mbochs_create()

Originally "type" could be NULL and these checks were required, but we
recently changed how "type" is assigned and that's no longer the case.
Now "type" points to an element in the middle of a non-NULL array.

Removing the checks does not affect runtime at all, but it makes the
code a little bit simpler to read.

Fixes: 3d3a360e

 ("vfio/mbochs: Use mdev_get_type_group_id()")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Message-Id: <20210429095327.GY1981@kadam>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>