Remove the now unnecessary extra call to transport_subsystem_check_init() in
target_core_register_fabric(), and also merge transport_subsystem_reqmods()
directly into transport_subsystem_check_init().
Reported-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>