drm/i915/dp: Initialise locals for static analysis

Just to squelch an smatch warning that doesn't see the with_() being
taken unconditionally:
drivers/gpu/drm/i915//intel_dp.c:230 intel_dp_get_fia_supported_lane_count() error: uninitialized symbol 'lane_info'.
drivers/gpu/drm/i915//intel_dp.c:5338 intel_digital_port_connected() error: uninitialized symbol 'is_connected'.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Imre Deak <imre.deak@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190517102225.3069-2-chris@chris-wilson.co.uk