bhyve/e1000: Assertion failed: (dtype == ntype), function e82545_transmit with win10 guest

[Yuri Pankov]

I'm getting the following periodically when Windows 10 (2004) guest is 
booting:

Assertion failed: (dtype == ntype), function e82545_transmit, file 
/usr/src/usr.sbin/bhyve/pci_e82545.c, line 1139.
Abort trap

It's especially unhelpful when booting the guest first time after 
installation as it completely breaks it and requires reinstall.

Running -current r364965.