freetdm: remove DTMF string from OOB events

libs/freetdm/src/include/private/ftdm_types.h

@@ -134,7 +134,7 @@ typedef enum {
 	FTDM_OOB_CAS_BITS_CHANGE,
 	FTDM_OOB_INVALID
 } ftdm_oob_event_t;
-#define OOB_STRINGS "DTMF", "ONHOOK", "OFFHOOK", "WINK", "FLASH", "RING_START", "RING_STOP", "ALARM_TRAP", "ALARM_CLEAR", "NOOP", "CAS_BITS_CHANGE", "INVALID"
+#define OOB_STRINGS "ONHOOK", "OFFHOOK", "WINK", "FLASH", "RING_START", "RING_STOP", "ALARM_TRAP", "ALARM_CLEAR", "NOOP", "CAS_BITS_CHANGE", "INVALID"
 FTDM_STR2ENUM_P(ftdm_str2ftdm_oob_event, ftdm_oob_event2str, ftdm_oob_event_t)
 
 typedef enum {