Introduce a device flags value of 0x1 to always pretend a 1.44 MB

Introduce a device flags value of 0x1 to always pretend a 1.44 MB
floppy drive #0, regardless of what the CMOS says.  This is intended
as a bandaid for those plagued with Compaq's idea to not announce the
floppy drive on their `Aero' notebook.

Using the device flags is not very nice (in particular since they
aren't per-drive but per-controller), but still looks a lot better to
me than the disgusting guesswork hack that was recently posted to
-hackers.

Doc update will follow shortly.