dahdi: Move 'timingslips' in with the other maintenance counters.

This allows timingslips to be reset along with the other counters and clarifies
the intended use.

This came up when Doug Bailey asked why he couldn't use dahdi_maint to clear
timing slips in addition to the other counters.

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

include/dahdi/kernel.h

@@ -750,6 +750,7 @@ struct dahdi_count {
 	__u32 be;		/*!< current bit error count */
 	__u32 prbs;		/*!< current PRBS detected pattern */
 	__u32 errsec;		/*!< errored seconds */
+	__u32 timingslips;	/*!< Clock slips */
 };
 
 /* map flagbits to flag masks */
@@ -955,8 +956,6 @@ struct dahdi_span {
 	int maintstat;			/*!< Maintenance state */
 	int mainttimer;			/*!< Maintenance timer */
 
-	int timingslips;		/*!< Clock slips */
-
 	struct dahdi_chan **chans;	/*!< Member channel structures */
 
 	const struct dahdi_span_ops *ops;	/*!< span callbacks. */