drm/amdgpu: Use ARRAY_SIZE for sos_old_versions

Fixes coccicheck warning:

drivers/gpu/drm/amd/amdgpu/psp_v3_1.c:182:40-41: WARNING: Use ARRAY_SIZE

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>