drm/edid: fix and clarify HDMI VSDB audio latency parsing

Add helpers for Latency_Fields_Present and I_Latency_Fields_Present
bits, and fix the parsing:

- Respect specification regarding "I_Latency_Fields_Present shall be
  zero if Latency_Fields_Present is zero".

- Don't claim latency fields are present if the data block isn't big
  enough to hold them.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/80426772a2d2e17bebf6f58d99b7d0cf6260c2d6.1672826282.git.jani.nikula@intel.com