media: rcar-vin: Use correct count of remote subdevices

When extending the driver with Gen4 support the iteration of over
possible remote subdevices changed from being R-Car CSI-2 Rx only to
also cover R-Car CSISP instances. In two loops updating the bounds
variable was missed.

This had no ill effect as the count the two values have always been the
same in the past. Fix it by looking at the array size.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Tested-by: Tomi Valkeinen <tomi.valkeinen+renesas@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Link: https://lore.kernel.org/r/20250613153434.2001800-2-niklas.soderlund+renesas@ragnatech.se


Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>