script: trim RTT log data on dictionary parser

The fact that log data captured with RTT has a header, like the
following, impedes the parser to parse the data properly

```
Trying ::1...
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
SEGGER J-Link V8.24 - Real time terminal output
SEGGER J-Trace PRO V4.0, SN=XXXX
Process: JLinkExe
```

Signed-off-by: Leonardo Bispo <[email protected]>

Author: ldab

scripts/logging/dictionary/log_parser.py

@@ -96,8 +96,19 @@ def read_log_file(args):
                 sys.exit(1)
             logdata = logfile.read()
 
+        # RTT logs add header information to the logdata, the actual log comes
+        # after newline following "Process:" line in logdata
+        if b"Process:" in logdata:
+            process_idx = logdata.find(b"Process:")
+            newline_idx = logdata.find(b"\n", process_idx)
+            if newline_idx != -1:
+                # Keep only the data after this newline
+                logdata = logdata[newline_idx + 1 :]
+                logger.debug("Found 'Process:' in the RTT header, trimmed data")
+
     return logdata
 
+
 def main():
     """Main function of log parser"""
     args = parse_args()