drm/radeon: Use drm_hdmi_avi_infoframe_quant_range()

Fill out the AVI infoframe quantization range bits using
drm_hdmi_avi_infoframe_quant_range() instead of hand rolling it.

This changes the behaviour slightly as
drm_hdmi_avi_infoframe_quant_range() will set a non-zero Q bit
even when QS==0 iff the Q bit matched the default quantization
range for the given mode. This matches the recommendation in
HDMI 2.0 and is allowed even before that.

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: "David (ChunMing) Zhou" <David1.Zhou@amd.com>
Cc: amd-gfx@lists.freedesktop.org
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190108172828.15184-3-ville.syrjala@linux.intel.com