media: staging: rkisp1: don't define vaddr field in rkisp1_buffer as an array

The field vaddr in rkisp1_buffer struct is used only by the
rkisp1-stats and rkisp1-params entities and they both use only
vaddr[0] so there is no need to define this field as an array.

Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
Acked-by: Helen Koike <helen.koike@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>