scsi: iscsi: qla4xxx: fix double free in probe

On this error path we call qla4xxx_mem_free() and then the caller also
calls qla4xxx_free_adapter() which calls qla4xxx_mem_free().  It leads to a
couple double frees:

drivers/scsi/qla4xxx/ql4_os.c:8856 qla4xxx_probe_adapter() warn: 'ha->chap_dma_pool' double freed
drivers/scsi/qla4xxx/ql4_os.c:8856 qla4xxx_probe_adapter() warn: 'ha->fw_ddb_dma_pool' double freed

Fixes: afaf5a2 ("[SCSI] Initial Commit of qla4xxx")
Link: https://lore.kernel.org/r/20191203094421.hw7ex7qr3j2rbsmx@kili.mountain
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/qla4xxx/ql4_os.c

@@ -4275,7 +4275,6 @@ static int qla4xxx_mem_alloc(struct scsi_qla_host *ha)
 	return QLA_SUCCESS;
 
 mem_alloc_error_exit:
-	qla4xxx_mem_free(ha);
 	return QLA_ERROR;
 }