drm/amdgpu: fix spelling mistake: "Successed" -> "Succeeded"

There is a spelling mistake in a deb_dbg message. Fix it.

Reviewed-by: Madhav Chauhan <madhav.chauhan@amd.com>
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>