[media] media: davinci: vpbe: use v4l2_fh for priority handling

This patch migrates the vpbe driver to use v4l2_fh for
priority handling. This also fixes v4l2-compliance test.

Signed-off-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>