drm/i915: move display-related to the end of intel_irq_init()

In intel_irq_init() move what's display/hpd related after what is gt and
guc. This makes it easier to support !HAS_DISPLAY() in future.

Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201106225531.920641-7-lucas.demarchi@intel.com