i915: add suspend/resume support

Add suspend/resume support to the i915 driver.  Moves some of the
initialization into the driver load routine, and fixes up places where we
assumed no dev_private existed in some of the cleanup paths.  This allows
us to suspend/resume properly even if X isn't running.

Signed-off-by: Dave Airlie <airlied@linux.ie>
diff --git a/drivers/char/drm/drm_bufs.c b/drivers/char/drm/drm_bufs.c
index d65e75d..07b774f 100644
--- a/drivers/char/drm/drm_bufs.c
+++ b/drivers/char/drm/drm_bufs.c
@@ -429,6 +429,7 @@
 
 	return ret;
 }
+EXPORT_SYMBOL(drm_rmmap);
 
 /* The rmmap ioctl appears to be unnecessary.  All mappings are torn down on
  * the last close of the device, and this is necessary for cleanup when things