drm/i915/display: Initialize capability variables

Initialize HDCP capability variables to false to avoid UBSAN
warning in boolean value as some functions invoking this could
return without filling the two capability values.

--v2
-Fix Typo [Chaitanya]

Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
Signed-off-by: Animesh Manna <animesh.manna@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240401030106.274787-2-suraj.kandpal@intel.com