itm: fix default initialization

Commit f9509c92db ("itm: rework itm commands before 'init'")
ignores the default enable of ITM channel 0, that is applied when
no 'itm port[s]' is issued.

Call armv7m_trace_itm_config() unconditionally to handle it.

Change-Id: I3e85d0b063ed38c1552f6af9ea9eea2e76aa9025
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reported-by: Paul Fertser <fercerpav@gmail.com>
Fixes: f9509c92db ("itm: rework itm commands before 'init'")
Reviewed-on: https://review.openocd.org/c/openocd/+/7900
Reviewed-by: <post@frankplowman.com>
Tested-by: jenkins

src/target/armv7m_trace.h

@@ -35,8 +35,6 @@ struct armv7m_trace_config {
 	bool itm_async_timestamps;
 	/** Enable synchronisation packet transmission (for sync port only) */
 	bool itm_synchro_packets;
-	/** Config ITM after target examine */
-	bool itm_deferred_config;
 };
 
 extern const struct command_registration armv7m_trace_command_handlers[];