Merge branch 'net-packet-make-packet_fanout-arr-size-configurable-up-to-64k'

Tanner Love says:

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net/packet: make packet_fanout.arr size configurable up to 64K

First patch makes the change; second patch adds unit tests.
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Link: https://lore.kernel.org/r/20201106180741.2839668-1-tannerlove.kernel@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>