drm: Add functions to setup/tear down drm_events.

An attempt at not spreading out the file_priv->event_space stuff out
quite so far and wide.  And I think fixes something in ipp_get_event()
that is broken (or if they are doing something more weird/subtle, then
breaks it in a fun way).

Based upon a patch from Rob Clark, rebased and polished.

v2: Spelling fixes (Alex).

Cc: Alex Deucher <alexdeucher@gmail.com>
Acked-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Cc: Rob Clark <robdclark@gmail.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1452548477-15905-3-git-send-email-daniel.vetter@ffwll.ch
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index a46a34f..04a6646 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -925,8 +925,13 @@
 		 size_t count, loff_t *offset);
 int drm_release(struct inode *inode, struct file *filp);
 int drm_new_set_master(struct drm_device *dev, struct drm_file *fpriv);
-
 unsigned int drm_poll(struct file *filp, struct poll_table_struct *wait);
+int drm_event_reserve_init(struct drm_device *dev,
+			   struct drm_file *file_priv,
+			   struct drm_pending_event *p,
+			   struct drm_event *e);
+void drm_event_cancel_free(struct drm_device *dev,
+			   struct drm_pending_event *p);
 
 /* Misc. IOCTL support (drm_ioctl.c) */
 int drm_noop(struct drm_device *dev, void *data,