media: rzv2h-ivc: Revise default VBLANK formula

media: rzv2h-ivc: Revise default VBLANK formula

The vertical blanking settings for the IVC block are dependent on
settings in the ISP. This was originally set to calculate as the
worst-case possible value, but it seems that this can cause the IVC
block to hang. Instead calculate the vblank to match the default
settings (which are currently all the driver sets anyway).

Cc: stable@vger.kernel.org
Fixes: f0b3984d821b ("media: platform: Add Renesas Input Video Control block driver")
Signed-off-by: Daniel Scally <dan.scally+renesas@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo.mondi+renesas@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>