drm: zte: remove leftover 'inf' from struct zx_hdmi

There is a leftover 'inf' field in struct zx_hdmi from commit
'831a8d5e ("drm: zte: move struct vou_inf into zx_vou driver")'.
Remove it.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/1490086795-17925-1-git-send-email-shawnguo@kernel.org