drm/i915/hdcp: Clean up zero initializers

Just use a simple {} to zero initialize arrays/structs instead
of the hodgepodge of stuff we are using currently.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231012122442.15718-3-ville.syrjala@linux.intel.com


Reviewed-by: Jani Nikula <jani.nikula@intel.com>