Add support for devices after /dev/sdp in aui-mkusb

[mozgwar]

According to this https://www.kernel.org/doc/Documentation/admin-guide/devices.txt
the last device of major number is /dev/sdp, to use devices after it aui-mkusb need to
check for major number 65, 66 etc ...

[mozgwar]

I did some test here and it seems that major number 41 is also used for block device:
LC_ALL=C stat -c %t /dev/sdy
41

[laurent85v]

I doubt it was allocated dynamically for a usb disk device.