arm/machine-summary: remove gn

gn was moved to oe-core.  So, we no longer need to track it as part of
the meta-arm CI machine-report

Signed-off-by: Jon Mason <jon.mason@arm.com>

scripts/machine-summary.py

@@ -141,7 +141,6 @@ def harvest_data(machines, recipes):
 recipes = ("boot-wrapper-aarch64",
            "edk2-firmware",
            "gator-daemon",
-           "gn",
            "hafnium",
            "opencsd",
            "optee-ftpm",