drm: add 32/64 support for MGA/R128/i915

This adds compatiblity ioctls for mga/r128 and i915 DRM drivers.

From: Paul Mackerras, David Airlie, Alan Hourihane, Egbert Eich.
Signed-off-by: David Airlie <airlied@linux.ie>
diff --git a/drivers/char/drm/r128_drv.h b/drivers/char/drm/r128_drv.h
index cf1aa5d..0fb687c9 100644
--- a/drivers/char/drm/r128_drv.h
+++ b/drivers/char/drm/r128_drv.h
@@ -156,6 +156,9 @@
 extern void r128_driver_pretakedown(drm_device_t *dev);
 extern void r128_driver_prerelease(drm_device_t *dev, DRMFILE filp);
 
+extern long r128_compat_ioctl(struct file *filp, unsigned int cmd,
+			      unsigned long arg);
+
 /* Register definitions, register access macros and drmAddMap constants
  * for Rage 128 kernel driver.
  */