media: platform: Delete vidioc_s_selection ioctl of jpeg dec

JPEG dec does't support setting a compose rectangle, so remove
mtk_jpeg_dec_s_selection().

Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Xia Jiang <xia.jiang@mediatek.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>