fteeprom-{erase,prog}: detach logic: change to detach by default As it turns out, detaching all ttyUSB interfaces of a multichannel device does not require outside knowledge of how many channels there are, as in our previous -d option design that is being removed here - instead we can read the bNumInterfaces constant from the USB device's config descriptor and thus know how many interfaces there are in total. Based on this discovery, change the design of fteeprom-{erase,prog} as follows: * remove -d option; * flip the default to where we detach all interfaces by default; * add -n option to NOT detach any interfaces.

# The following EEPROM image has been read out of a USB to RS232 (DE9M) cable
# that contains an FT232BM chip; it is not clear if the cable itself is an FTDI
# product or not.

00: 0000 0403 6001 0400 16A0 0008 0110 0A94
10: 2A9E 12C8 030A 0046 0054 0044 0049 032A
20: 0055 0053 0042 0020 0053 0065 0072 0069
30: 0061 006C 0020 0043 006F 006E 0076 0065
40: 0072 0074 0065 0072 0312 0046 0054 0044
50: 0049 0043 0033 0049 004B 0302 0000 0000
60: 0000 0000 0000 0000 0000 0000 0000 0000
70: 0000 0000 0000 0000 0000 0000 0001 C08B