be2iscsi: Fix kernel panic when device initialization fails

Kernel panic was happening as iscsi_host_remove() was called on
a host which was not yet added.

Signed-off-by: John Soni Jose <sony.john-n@emulex.com>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Cc: <stable@vger.kernel.org>
Signed-off-by: James Bottomley <JBottomley@Odin.com>