The USB descriptor sizes are specified as 16-bit for idVendor /
idProduct, and 8-bit for bInterfaceClass / bInterfaceSubClass /
bInterfaceProtocol. Doing so we reduce the usbredir_raw_serial_ids[]
and usbredir_ftdi_serial_ids[] arrays from 16KiB to 6KiB (size
reported on x86_64 host, building with --extra-cflags=-Os).

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>