net: ieee802154: hwsim: Ensure frame checksum are valid

There is no point in accepting frames with a wrong or missing checksum,
at least not outside of a promiscuous setting. Set the right flag by
default in the hwsim driver to ensure checksums are not ignored.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Alexander Aring <aahringo@redhat.com>
Link: https://lore.kernel.org/r/20220125122540.855604-2-miquel.raynal@bootlin.com
Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>