In target_fabric_configfs_init(), we should allow fabric_mod to be NULL,
since THIS_MODULE is NULL for built-in modules.  The main method of
using the target code may be as modules, but having everything built-in
is useful eg to be able to do quick testing with "qemu -kernel".

In any case, we shouldn't bomb out fabric registration for a perfectly
valid configuration, so simply drop the check of fabric_mod.
Signed-off-by: NRoland Dreier <roland@purestorage.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>