Add r8a774a1 specific compatible string.
Signed-off-by: NFabrizio Castro <fabrizio.castro@bp.renesas.com>
Reviewed-by: NBiju Das <biju.das@bp.renesas.com>
Reviewed-by: NSimon Horman <horms+renesas@verge.net.au>
Signed-off-by: NEduardo Valentin <edubezval@gmail.com>