Use of floppy disks and parallel ATA on amd64

[Thor Lancelot Simon <tls%panix.com@localhost>]

I would like to remove ISA floppy disk support (the ACPI attachment for
'fdc'; the ISA attachment is already commented out) from amd64 GENERIC.

I would also like to disable support for old parallel ATA drives (those
not supporting 48-bit LBA mode, and thus limited to 128K -1 block transfers).

I'd like to do this to allow us to increase MAXPHYS to 128K or more in amd64
GENERIC, improving I/O throughput.

If anyone's using these devices on amd64 and is not comfortable building a
custom kernel, could you please speak up?

Thanks!

Thor