pre-upload: coreboot: Allow C99-style comments

These comments are allowed in coreboot according to the coreboot style
guide.

TEST=Manual. Try to push coreboot patch with C99 comments, verify no
error / warning is encountered.
BUG=None.

Change-Id: I7a9e2dcc59b780a76ff0b01ffb1ced3b6d4f9380
Reviewed-on: https://chromium-review.googlesource.com/213860
Tested-by: Shawn Nematbakhsh <shawnn@chromium.org>
Reviewed-by: Stefan Reinauer <reinauer@chromium.org>
Commit-Queue: Shawn Nematbakhsh <shawnn@chromium.org>
diff --git a/pre-upload.py b/pre-upload.py
index 17ceb82..88f8c03 100755
--- a/pre-upload.py
+++ b/pre-upload.py
@@ -865,7 +865,7 @@
       '--min-conf-desc-length=2',
       '--no-tree',
       '--ignore=NEW_TYPEDEFS,PREFER_PACKED,PREFER_PRINTF,PREFER_ALIGNED,'
-      'GLOBAL_INITIALISERS,INITIALISED_STATIC'])
+      'GLOBAL_INITIALISERS,INITIALISED_STATIC,C99_COMMENTS'])
 
 
 def _kernel_configcheck(_project, commit):