Two extra messages required after sending a baud rate update, as observed

Two extra messages required after sending a baud rate update, as observed
in the linux mct_u232 driver, which apparently got them by sniffing usb
traffic from the vendor's windows 98 driver.  Makes this device work at
115200:

umct0 at uhub0 port 2 "Belkin Components F5U109 Serial" rev 1.10/1.02 addr 2

ok dlg@