drm/amdgpu: update ATHUB_MISC_CNTL offset for athub v3.3

This patch to update ATHUB_MISC_CNTL offset for athub v3.3

v2: correct a typo (Tim)
v3: correct patch title (Lang)

Signed-off-by: Yifan Zhang <yifan1.zhang@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Tim Huang <Tim.Huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>