scsi: qla2xxx: Fix possible fcport null-pointer dereferences

In qla2x00_alloc_fcport(), fcport is assigned to NULL in the error
handling code on line 4880:
    fcport = NULL;

Then fcport is used on lines 4883-4886:
    INIT_WORK(&fcport->del_work, qla24xx_delete_sess_fn);
	INIT_WORK(&fcport->reg_work, qla_register_fcport_fn);
	INIT_LIST_HEAD(&fcport->gnl_entry);
	INIT_LIST_HEAD(&fcport->list);

Thus, possible null-pointer dereferences may occur.

To fix these bugs, qla2x00_alloc_fcport() directly returns NULL
in the error handling code.

These bugs are found by a static analysis tool STCheck written by us.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Acked-by: Himanshu Madhani <hmadhani@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>