media: adv748x: csi2: Set virtual channel when device is reset

It's not enough to set the CSI-2 virtual channel for TXA and TXB during
probe: it also needs to be set when the device is reset. Move the virtual
channel selection to adv748x_reset() that is called during probe and
when the device needs to be reset.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>