Change return value on error.

On wrong parameters a error is signalized to the calling function.

Change-Id: I484443fdb39938e20382edc9246d5ec546a5c960
Signed-off-by: Mathias K <kesmtp@freenet.de>
Signed-off-by: Øyvind Harboe <oyvind.harboe@zylin.com>
Reviewed-on: http://openocd.zylin.com/282
Tested-by: jenkins
Reviewed-by: Øyvind Harboe <oyvindharboe@gmail.com>

src/target/mips32.c

@@ -797,7 +797,7 @@ COMMAND_HANDLER(mips32_handle_cp0_command)
 	/* two or more argument, access a single register/select (write if third argument is given) */
 	if (CMD_ARGC < 2)
 	{
-		command_print(CMD_CTX, "command requires more arguments.");
+	    return ERROR_COMMAND_SYNTAX_ERROR;
 	}
 	else
 	{