be2net: Fix NULL pointer dereference in be_cmd_get_mac_from_list

When the parameter pmac_id_valid argument of be_cmd_get_mac_from_list() is
set to false, the driver may request the PMAC_ID from the firmware of the
network card, and this function will store that PMAC_ID at the provided
address pmac_id. This is the contract of this function.

However, there is a location within the driver where both
pmac_id_valid == false and pmac_id == NULL are being passed. This could
result in dereferencing a NULL pointer.

To resolve this issue, it is necessary to pass the address of a stub
variable to the function.

Fixes: 95046b927a54 ("be2net: refactor MAC-addr setup code")
Signed-off-by: Andrey Vatoropin <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/net/ethernet/emulex/benet/be_cmds.c

···
 {
 	int status;
 	bool pmac_valid = false;
+	u32 pmac_id;
 
 	eth_zero_addr(mac);
 
···
 						       adapter->if_handle, 0);
 	} else {
 		status = be_cmd_get_mac_from_list(adapter, mac, &pmac_valid,
-						  NULL, adapter->if_handle, 0);
+						  &pmac_id, adapter->if_handle, 0);
 	}
 
 	return status;