[build] Add missing #include <config/local/sideband.h>

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/config/sideband.h

@@ -12,4 +12,6 @@ FILE_LICENCE ( GPL2_OR_LATER );
 //#define	CONFIG_BOFM	/* IBM's BladeCenter Open Fabric Manager */
 //#define	VMWARE_SETTINGS	/* VMware GuestInfo settings */
 
+#include <config/local/sideband.h>
+
 #endif /* CONFIG_SIDEBAND_H */