drm/i915/cnl: Allow the reg_read ioctl to read the RCS TIMESTAMP register

This enables the Mesa driver to advertise support for ARB_timer_query, and
thus an OpenGL version higher than 3.2.

Suggested-by: Ben Widawsky <ben@bwidawsk.net>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Nanley Chery <nanley.g.chery@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170905184507.30046-1-nanley.g.chery@intel.com

drivers/gpu/drm/i915/intel_uncore.c

@@ -1251,7 +1251,7 @@ static const struct register_whitelist {
 } whitelist[] = {
 	{ .offset_ldw = RING_TIMESTAMP(RENDER_RING_BASE),
 	  .offset_udw = RING_TIMESTAMP_UDW(RENDER_RING_BASE),
-	  .size = 8, .gen_bitmask = GEN_RANGE(4, 9) },
+	  .size = 8, .gen_bitmask = GEN_RANGE(4, 10) },
 };
 
 int i915_reg_read_ioctl(struct drm_device *dev,