mailmap: Add entry for old intel email

Fix old email to avoid bouncing email from net/drivers and older
netdev work. Anyways my @intel email hasn't been active for years.

Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/r/20230717173306.38407-1-john.fastabend@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: jrfastab

.mailmap

@@ -241,6 +241,7 @@ Jisheng Zhang <jszhang@kernel.org> <Jisheng.Zhang@synaptics.com>
 Johan Hovold <johan@kernel.org> <jhovold@gmail.com>
 Johan Hovold <johan@kernel.org> <johan@hovoldconsulting.com>
 John Crispin <john@phrozen.org> <blogic@openwrt.org>
+John Fastabend <john.fastabend@gmail.com> <john.r.fastabend@intel.com>
 John Keeping <john@keeping.me.uk> <john@metanate.com>
 John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
 John Stultz <johnstul@us.ibm.com>