drm/i915: report correct render clock frequencies on SNB

Fix up the debug file to report the right frequencies.  On SNB, we program
the PCU with a frequency ratio, which is multiplied by 100MHz on the CPU
side.  But GFX only runs at half that, so report it as such to avoid
confusion.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Keith Packard <keithp@keithp.com>
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 49c0723..432fc04 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -6930,7 +6930,7 @@
 		DRM_ERROR("timeout waiting for pcode mailbox to finish\n");
 	if (pcu_mbox & (1<<31)) { /* OC supported */
 		max_freq = pcu_mbox & 0xff;
-		DRM_DEBUG_DRIVER("overclocking supported, adjusting frequency max to %dMHz\n", pcu_mbox * 100);
+		DRM_DEBUG_DRIVER("overclocking supported, adjusting frequency max to %dMHz\n", pcu_mbox * 50);
 	}
 
 	/* In units of 100MHz */