media: amphion: Replace zero-length array with flexible-array member

There is a regular need in the kernel to provide a way to declare
having a dynamically sized set of trailing elements in a structure.
Kernel code should always use “flexible array members”[1] for these
cases. The older style of one-element or zero-length arrays should no
longer be used[2][3].

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/latest/process/deprecated.html#zero-length-and-one-element-arrays
[3] https://github.com/KSPP/linux/issues/78

Fixes: 9f599f35

 ("media: amphion: add vpu core driver")
Cc: Ming Qian <ming.qian@nxp.com>
Cc: Shijie Qin <shijie.qin@nxp.com>
Cc: Zhou Peng <eagle.zhou@nxp.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: ming_qian <ming.qian@nxp.com>
Reviewed-by: Tommaso Merciai <tommaso.merciai@amarulasolutions.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>