drm/amd/amdgpu: Properly tune the size of struct

The struct assertion is failed because sparse cannot parse
`#pragma pack(push, 1)` and `#pragma pack(pop)` correctly.
GCC's output is still 1-byte-aligned. No harm to memory layout.

The error can be filtered out by sparse-diff, but sometimes
multiple lines queezed into one, making the sparse-diff thinks
its a new error. I'm trying to aviod this by fixing errors.

Link: https://lore.kernel.org/all/20230620045919.492128-1-suhui@nfschina.com/
Link: https://lore.kernel.org/all/93d10611-9fbb-4242-87b8-5860b2606042@suswa.mountain/


Fixes: 1721bc1b ("drm/amdgpu: Update VF2PF interface")
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: wenlunpeng <wenlunpeng@uniontech.com>
Reported-by: Su Hui <suhui@nfschina.com>
Signed-off-by: WangYuli <wangyuli@uniontech.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>