arm64: dts: renesas: ebisu: Enable VIN5

Both VIN4 and VIN5 are connected to CSI40 and can be configured at
runtime to use the single video source connected to CSI40. Enable VIN5
to allow it to be used in this fashion.

Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
[Niklas: rewrite commit message]
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>