l3cfg: forward declare NML3ConfigData in "nm-types.h"

src/nm-l3-config-data.h

@@ -63,8 +63,6 @@ typedef enum {
 
 /*****************************************************************************/
 
-typedef struct _NML3ConfigData NML3ConfigData;
-
 typedef struct {
 	const NML3ConfigData *l3cd;
 	NML3ConfigMergeFlags merge_flags;

src/nm-types.h

@@ -24,6 +24,7 @@ typedef struct _NMConfig             NMConfig;
 typedef struct _NMConfigData         NMConfigData;
 typedef struct _NMConnectivity       NMConnectivity;
 typedef struct _NML3Cfg              NML3Cfg;
+typedef struct _NML3ConfigData       NML3ConfigData;
 typedef struct _NMDevice             NMDevice;
 typedef struct _NMDhcpConfig         NMDhcpConfig;
 typedef struct _NMProxyConfig        NMProxyConfig;