Remove the DTS file for the no longer supported Mackerel board.
Signed-off-by: NMagnus Damm <damm+renesas@opensource.se>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>