target: fix syntax in help message

The name of the command is already printed before the string
in ->usage, thus it appears twice.
E.g.
	> help examine
	  stm32f4x.cpu arp_examine arp_examine ['allow-defer']
	        used internally for reset processing
	  stm32f4x.cpu examine_deferred examine_deferred
	        used internally for reset processing
	  stm32f4x.cpu was_examined was_examined
	        used internally for reset processing

Remove the command name from the string in ->usage.

Change-Id: If3b1368ffff8a94eb629ae3679e2e5f2f11ae92e
Signed-off-by: Antonio Borneo <[email protected]>
Reviewed-on: http://openocd.zylin.com/4536
Tested-by: jenkins
Reviewed-by: Matthias Welwarsky <[email protected]>

src/target/target.c

@@ -5433,21 +5433,19 @@ static const struct command_registration target_instance_command_handlers[] = {
 		.mode = COMMAND_EXEC,
 		.jim_handler = jim_target_examine,
 		.help = "used internally for reset processing",
-		.usage = "arp_examine ['allow-defer']",
+		.usage = "['allow-defer']",
 	},
 	{
 		.name = "was_examined",
 		.mode = COMMAND_EXEC,
 		.jim_handler = jim_target_was_examined,
 		.help = "used internally for reset processing",
-		.usage = "was_examined",
 	},
 	{
 		.name = "examine_deferred",
 		.mode = COMMAND_EXEC,
 		.jim_handler = jim_target_examine_deferred,
 		.help = "used internally for reset processing",
-		.usage = "examine_deferred",
 	},
 	{
 		.name = "arp_halt_gdb",