Add Jeff Kirsher to .get_maintainer.ignore

Jeff was retired as the Intel driver maintainer in
commit 6667df91

 ("MAINTAINERS: Update MAINTAINERS for
Intel ethernet drivers"), and his address bounces.
But he has signed-off a lot of patches over the years
so get_maintainer insists on CCing him.

We haven't heard from him since he left Intel, so remapping
the address via mailmap is also pointless. Add to ignored
addresses.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>