scsi: qla2xxx: Fix double free of the ha->vp_map pointer

Coverity scan reported potential risk of double free of the pointer
ha->vp_map.  ha->vp_map was freed in qla2x00_mem_alloc(), and again freed
in function qla2x00_mem_free(ha).

Assign NULL to vp_map and kfree take care of NULL.

Cc: [email protected]
Signed-off-by: Saurav Kashyap <[email protected]>
Signed-off-by: Nilesh Javali <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Himanshu Madhani <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

Author: Saurav Kashyap

drivers/scsi/qla2xxx/qla_os.c

@@ -4602,6 +4602,7 @@ qla2x00_mem_alloc(struct qla_hw_data *ha, uint16_t req_len, uint16_t rsp_len,
 	ha->init_cb_dma = 0;
 fail_free_vp_map:
 	kfree(ha->vp_map);
+	ha->vp_map = NULL;
 fail:
 	ql_log(ql_log_fatal, NULL, 0x0030,
 	    "Memory allocation failure.\n");