drm/i915/gvt: replace I915_WRITE with intel_uncore_write

Let's avoid adding new I915_WRITE uses while we try to get rid of them.

Fixes: 5f60b12e ("drm/i915/gvt: Save/restore HW status to support GVT suspend/resume")
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Hang Yuan <hang.yuan@linux.intel.com>
Cc: Colin Xu <colin.xu@intel.com>
Cc: Zhi Wang <zhi.a.wang@intel.com>
Cc: intel-gvt-dev@lists.freedesktop.org
Reviewed-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201130111601.2817-9-jani.nikula@intel.com

drivers/gpu/drm/i915/gvt/handlers.c

@@ -3652,7 +3652,7 @@ static inline int mmio_pm_restore_handler(struct intel_gvt *gvt,
 	struct drm_i915_private *dev_priv = gvt->gt->i915;
 
 	if (gvt->mmio.mmio_attribute[offset >> 2] & F_PM_SAVE)
-		I915_WRITE(_MMIO(offset), vgpu_vreg(vgpu, offset));
+		intel_uncore_write(&dev_priv->uncore, _MMIO(offset), vgpu_vreg(vgpu, offset));
 
 	return 0;
 }