[media] media: ti-vpe: vpe: allow use of user specified stride

Bytesperline/stride was always overwritten by VPE to the most
adequate value based on needed alignment.

However in order to make use of arbitrary size DMA buffer it
is better to use the user space provide stride instead.

The driver will still calculate an appropriate stride but will
use the provided one when it is larger than the calculated one.

Signed-off-by: Benoit Parrot <bparrot@ti.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>