[ot] scripts/opentitan: use Python 3.9 syntax for type unions

Signed-off-by: James Wainwright <james.wainwright@lowrisc.org>

Author: jwnrt

scripts/opentitan/flashgen.py

@@ -18,7 +18,7 @@
                      join as joinpath, normpath)
 from struct import calcsize as scalc, pack as spack, unpack as sunpack
 from traceback import format_exc
-from typing import Any, BinaryIO, NamedTuple, Optional
+from typing import Any, BinaryIO, NamedTuple, Optional, Union
 import re
 import sys
 
@@ -216,7 +216,7 @@ def info_part_size(cls) -> int:
         return sum(cls.INFOS) * cls.BYTES_PER_PAGE
 
     def read_boot_info(self) -> dict[BootLocation,
-                                     dict[str, [int | bytes]]]:
+                                     dict[str, Union[int, bytes]]]:
         size = self._boot_header_size
         fmt = ''.join(self.BOOT_HEADER_FORMAT.values())
         boot_entries = {}

scripts/opentitan/gdbreplay.py

@@ -17,7 +17,7 @@
                     timeout as LegacyTimeoutError)
 from string import ascii_uppercase
 from traceback import format_exc
-from typing import BinaryIO, Optional, TextIO
+from typing import BinaryIO, Optional, TextIO, Union
 import re
 import sys
 
@@ -461,7 +461,7 @@ def _send(self, payload: str):
         self._log.info('Reply: "%s"', payload)
         self._send_bytes(payload.encode())
 
-    def _send_bytes(self, payload: [bytes | bytearray]):
+    def _send_bytes(self, payload: Union[bytes, bytearray]):
         """Send a reply to the remote GDB client.
 
            :param payload: the byte sequence to send