drm/i915: convert VLV IOSF SB interface to struct drm_device

drm/i915: convert VLV IOSF SB interface to struct drm_device

With users both in i915 core and display, struct drm_device is the
common denominator for the VLV IOSF SB users. Also use drm_device for
the helpers on the display side to keep the static inlines as simple as
possible.

We can drop a number of dependencies on i915_drv.h with this.

v2,v3: Rebase

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://lore.kernel.org/r/c1d013ed88ce2e3e5bdc15ce3bf01a3960b1e817.1747061743.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>