drm/i915/crt: convert to struct intel_display

struct intel_display will replace struct drm_i915_private as the main
device pointer for display code. Switch CRT code over to it.

v2: Rebase

Reviewed-by: Rodrigo Vivi <[email protected]>
Signed-off-by: Jani Nikula <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

Author: jnikula