drm/i915: Do not override mode's aspect ratio with the prop value NONE

drm/i915: Do not override mode's aspect ratio with the prop value NONE

HDMI_PICTURE_ASPECT_NONE means "Automatic" so when the user has that
selected we should keep whatever aspect ratio the mode already has.

Also no point in checking for connector->is_hdmi in the SDVO code
since we only attach the property to HDMI connectors.

Cc: Ilia Mirkin <imirkin@alum.mit.edu>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190620142639.17518-5-ville.syrjala@linux.intel.com
Reviewed-by: Uma Shankar <uma.shankar@intel.com>