fix doc-string in GetFilesSplitByOwners

Forgot to upload a new patchset with the fix before the submit
in https://crrev.com/c/6484531

Bug: 412904761
Change-Id: I811bd31aeab62f3732a7fb21789b66ee8aa66336
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/6489290
Auto-Submit: Scott Lee <ddoman@chromium.org>
Commit-Queue: Gavin Mak <gavinmak@google.com>
Reviewed-by: Gavin Mak <gavinmak@google.com>

split_cl.py

@@ -330,7 +330,7 @@ def GetFilesSplitByOwners(files, max_depth, repository_root):
         files: List of the file paths to be grouped by the OWNERS.
             Note that each path is relative to the repostiory root.
         max_depth: Max depth to traverse from the repository path.
-        repository_path: Absolute path to the repository root.
+        repository_root: Absolute path to the repository root.
 
     Returns:
         A map where keys are paths to directories containing an OWNERS file and