scripts/gdb/symbols: fix invalid escape sequence warning

With python 3.12, '\.' results in this warning
    SyntaxWarning: invalid escape sequence '\.'

Link: https://lkml.kernel.org/r/20240304012507.240380-1-andrewjballance@gmail.com
Signed-off-by: Andrew Ballance <andrewjballance@gmail.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Kieran Bingham <kbingham@kernel.org>
Cc: Koudai Iwahori <koudai@google.com>
Cc: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: mrwigglewaffles

scripts/gdb/linux/symbols.py

@@ -82,7 +82,7 @@ def _update_module_files(self):
         self.module_files_updated = True
 
     def _get_module_file(self, module_name):
-        module_pattern = ".*/{0}\.ko(?:.debug)?$".format(
+        module_pattern = r".*/{0}\.ko(?:.debug)?$".format(
             module_name.replace("_", r"[_\-]"))
         for name in self.module_files:
             if re.match(module_pattern, name) and os.path.exists(name):