drm/i915/display: include intel_uncore.h where needed

Include what you use. With this, we can drop the include from xe compat
i915_drv.h.

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/bc3a722413e20db905671e58627ba6d757f41c63.1717004739.git.jani.nikula@intel.com