ARM: dts: silk: Drop unnecessary address properties from vin port node

The vin port node does not have an address and thus does not need
address-cells or address size-properties.

This is flagged by dtc as follows:
 # make dtbs W=1
 arch/arm/boot/dts/r8a7794-silk.dtb: Warning (avoid_unnecessary_addr_size): /soc/video@e6ef0000/port: unnecessary #address-cells/#size-cells without "ranges" or child "reg" property

Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>