media: amphion: adjust the encoder's value range of gop size

media: amphion: adjust the encoder's value range of gop size

adjust the value range of gop size from [0, 65535] to [1, 8000].
when the gop size is set to a too large value,
it may affect the encoded picture quality.
so constrain it to a reasonable range.

Fixes: 0401e659c1f92 ("media: amphion: add v4l2 m2m vpu encoder stateful driver")
Signed-off-by: Ming Qian <ming.qian@nxp.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>