drm: drm_atomic.h: delete duplicated word in comment

Drop doubled word "than" in a comment.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20200715052349.23319-1-rdunlap@infradead.org

include/drm/drm_atomic.h

@@ -103,7 +103,7 @@ struct drm_crtc_commit {
 	 *
 	 * Will be signalled when all hw register changes for this commit have
 	 * been written out. Especially when disabling a pipe this can be much
-	 * later than than @flip_done, since that can signal already when the
+	 * later than @flip_done, since that can signal already when the
 	 * screen goes black, whereas to fully shut down a pipe more register
 	 * I/O is required.
 	 *