drm/i915: call intel_enable_gtt

When drm/i915 is in control of the gtt, we need to call
the enable function at all the relevant places ourselves.

Reviewed-by: Jani Nikula <jani.nikula@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/char/agp/intel-gtt.c b/drivers/char/agp/intel-gtt.c
index 4387e69..419a25e 100644
--- a/drivers/char/agp/intel-gtt.c
+++ b/drivers/char/agp/intel-gtt.c
@@ -777,7 +777,7 @@
 	writel(addr | pte_flags, intel_private.gtt + entry);
 }
 
-static bool intel_enable_gtt(void)
+bool intel_enable_gtt(void)
 {
 	u8 __iomem *reg;
 
@@ -823,6 +823,7 @@
 
 	return true;
 }
+EXPORT_SYMBOL(intel_enable_gtt);
 
 static int i830_setup(void)
 {