wpa_supplicant: Parent interface should know about its dedicated P2P dev

This will be useful to hand-off P2P commands from the parent interface
to its dedicated P2P device if that one is present, in DBus interface.

Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>

wpa_supplicant/p2p_supplicant.c

@@ -3957,6 +3957,7 @@ int wpas_p2p_add_p2pdev_interface(struct wpa_supplicant *wpa_s,
 		return -1;
 	}
 	p2pdev_wpa_s->parent = wpa_s;
+	wpa_s->p2p_dev = p2pdev_wpa_s;
 
 	wpa_s->pending_interface_name[0] = '\0';
 	return 0;

wpa_supplicant/wpa_supplicant_i.h

@@ -688,6 +688,7 @@ struct wpa_supplicant {
 	int p2p_mgmt;
 
 #ifdef CONFIG_P2P
+	struct wpa_supplicant *p2p_dev;
 	struct p2p_go_neg_results *go_params;
 	int create_p2p_iface;
 	u8 pending_interface_addr[ETH_ALEN];