media: uapi: mpeg2: Rename "quantization" to "quantisation"

The MPEG-2 specification refers to the quantisation matrices
using the word "quantisation". Make the V4L2 interface more
ergonomic by matching the MPEG-2 spec.

Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Tested-by: Jernej Skrabec <jernej.skrabec@siol.net>
Reviewed-by: Jernej Skrabec <jernej.skrabec@siol.net>
Tested-by: Daniel Almeida <daniel.almeida@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>