dahdi: Embed the proc entries in struct dahdi_span.

Part of preparations for replacing the array of spans with a list of
spans.

Review: https://reviewboard.asterisk.org/r/905/

Signed-off-by: Shaun Ruffell <sruffell@digium.com>

git-svn-id: http://svn.asterisk.org/svn/dahdi/linux/trunk@9354 a0bf4364-ded3-4de4-8d8a-66a801d63aff

include/dahdi/kernel.h

@@ -871,6 +871,10 @@ struct dahdi_span {
 	int watchcounter;
 	int watchstate;
 #endif	
+
+#ifdef CONFIG_PROC_FS
+	struct proc_dir_entry *proc_entry;
+#endif
 };
 
 struct dahdi_transcoder_channel {