drm/i915: Extend non readable mcr range

Our current avoidance of non readable mcr range was not
inclusive enough. Extend the start and end.

References: HSDES#1405586840
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Acked-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190809145653.2279-1-mika.kuoppala@linux.intel.com

drivers/gpu/drm/i915/gt/intel_workarounds.c

@@ -1453,7 +1453,7 @@ static bool mcr_range(struct drm_i915_private *i915, u32 offset)
 	 * which only controls CPU initiated MMIO. Routing does not
 	 * work for CS access so we cannot verify them on this path.
 	 */
-	if (INTEL_GEN(i915) >= 8 && (offset >= 0xb100 && offset <= 0xb3ff))
+	if (INTEL_GEN(i915) >= 8 && (offset >= 0xb000 && offset <= 0xb4ff))
 		return true;
 
 	return false;