tools/cfi: fix a typo in the path to Dawn

Bug: chromium:1139232
Change-Id: I5be89203e8797a58234a2bee88f9efafc09a6d80
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2478951Reviewed-by: Austin Eng <enga@chromium.org>
Reviewed-by: Marc Treib <treib@chromium.org>
Reviewed-by: Peter Collingbourne <pcc@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#818135}

tools/cfi/ignores.txt

@@ -140,7 +140,7 @@ fun:*GetTraceCategoryEnabledFlag*
 fun:*AddTraceEvent*
 
 # Dawn, calls to OpenGL and Vulkan function pointers from shared library.
-src:*third_part/dawn/src/dawn_native/*
+src:*third_party/dawn/src/dawn_native/*
 
 # PPAPI
 src:*ppapi/*