nv: Use dev_remove_param to delete nv variable

dev_remove_param() is exactly for the purpose of removing a device
parameter, so use this function instead of open coding the
functionality.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

common/globalvar.c

@@ -304,13 +304,12 @@ int nvvar_remove(const char *name)
 		return -ENOENT;
 
 	fname = basprintf("/env/nv/%s", p->name);
+
+	dev_remove_param(p);
+
 	unlink(fname);
 	free(fname);
 
-	list_del(&p->list);
-	free(p->name);
-	free(p);
-
 	return 0;
 }