drm/i915: make more uncore function work on intel_uncore

Move the init, fini, prune, suspend, resume function to work on
intel_uncore instead of dev_priv.

Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190319183543.13679-5-daniele.ceraolospurio@intel.com