usb: dfu: add static alt num count in dfu_config_entities()

Thanks to this multiple call of function dfu_config_entities()
gives continuous dfu alt numbering until call dfu_free_entities().

This allows to store dfu entities in multiple variables.

Signed-off-by: Przemyslaw Marczak <p.marczak@samsung.com>
Acked-by: Łukasz Majewski <l.majewski@samsung.com>
Tested-by: Heiko Schocher <hs@denx.de>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>

drivers/dfu/dfu.c

@@ -19,6 +19,7 @@
 static bool dfu_reset_request;
 static LIST_HEAD(dfu_list);
 static int dfu_alt_num;
+static int alt_num_cnt;
 
 bool dfu_reset(void)
 {
@@ -377,6 +378,8 @@ void dfu_free_entities(void)
 	if (t)
 		free(t);
 	INIT_LIST_HEAD(&dfu_list);
+
+	alt_num_cnt = 0;
 }
 
 int dfu_config_entities(char *env, char *interface, int num)
@@ -394,11 +397,12 @@ int dfu_config_entities(char *env, char *interface, int num)
 	for (i = 0; i < dfu_alt_num; i++) {
 
 		s = strsep(&env, ";");
-		ret = dfu_fill_entity(&dfu[i], s, i, interface, num);
+		ret = dfu_fill_entity(&dfu[i], s, alt_num_cnt, interface, num);
 		if (ret)
 			return -1;
 
 		list_add_tail(&dfu[i].list, &dfu_list);
+		alt_num_cnt++;
 	}
 
 	return 0;