[SCSI] be2iscsi: fix memory leak on error path

I added a kfree(pwrb_arr) in front of the return.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>