signer: Update mkfs.erofs pcluster value to 32K

... to be consistent with board_specific_setup.py
in crrev/i/6625758

BUG=b:309722489
BRANCH=None
TEST=Run with an EROFS Android image

Change-Id: I577a3175f9d14b85e7e6b33cd611f0122ef4f1ae
Signed-off-by: Satoshi Niwa <niwa@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/5009619
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Alexandre Marciano Gimenez <raging@google.com>
diff --git a/scripts/image_signing/sign_android_image.sh b/scripts/image_signing/sign_android_image.sh
index b928e59..90e73d2 100755
--- a/scripts/image_signing/sign_android_image.sh
+++ b/scripts/image_signing/sign_android_image.sh
@@ -558,7 +558,7 @@
     info "Repacking erofs image"
     # TODO(b/286165395): Detect the original EROFS compression type and use it
     #                    instead of always using lz4hc.
-    sudo "${mkfs_erofs}" -z lz4hc -C262144 --file-contexts "${file_contexts}" \
+    sudo "${mkfs_erofs}" -z lz4hc -C32768 --file-contexts "${file_contexts}" \
       "${system_img}" "${system_mnt}"
   fi