media: platform: ti: Remove unused vpdma_update_dma_addr

vpdma_update_dma_addr() was added in 2016 as part of
commit 2f88703a ("[media] media: ti-vpe: vpdma: Add multi-instance and
multi-client support")

but has remained unused.

Remove it.

I did see that there was a VIP driver submitted in 2020 that
doesn't seem to have got merged which did use this (and a bunch
of other unused functions).

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>