apply a fix by Steven Chamberlain <steven@pyro.eu.org>, via freebsd:
apply a fix by Steven Chamberlain <steven@pyro.eu.org>, via freebsd:

Fix an issue with 11g beacon frames which looks to be a limitation
on the largest multi-write size:

==
I looked further into the magic 88-byte threshold after which the bug
occurs.  It turns out that figure included the 24-byte tx_desc, and up
to 64 bytes of beacon frame (header+data).

rum_write_multi doesn't seem happy with writing >64 bytes at a time to
the MAC register.  If I break it up into separate calls (e.g. bytes
0-63, then bytes 64-65, written at the appropriate offset) I see the
proper beacon frames being transmitted now.
==

tweak by miod@
ok deraadt@

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars