Fix hang on GIGABYTE keyboard

[KurtE]

resolves #40

0 length items in the configuration descriptor.

As I mentioned in the issue: There as some devices who have 0 length fields within their configuration descriptor
Example GIGABYTE keyboard.

Configuration Descriptor
2400E8F0 - 09 02 54 00 03 01 00 A0  32 09 04 00 00 01 03 01  : ..T..... 2.......
2400E900 - 01 00 09 21 10 01 00 01  22 3B 00 07 05 81 03 08  : ...!.... ";......
2400E910 - 00 08 09 04 01 00 01 03  01 22 51 00 07 05 82 03  : ........ ."Q.....
2400E920 - 10 00 08 09 04 02 00 01  03 00 00 00 09 21 10 01  : ........ .....!..
2400E930 - 00 01 22 25 00 07 05 83  03 10 00 01 00 00 00 00  : .."%.... ........
2400E940 - 00 00 00 00                                       : ....

The issue came up before on another USBHost library (USBHost_t36).
The solution is when you find a zero length field, you simply increment to the next byte.

It works on my WIP branch, however here hard to test as the current released code fails to read in the full descriptors.
But that is a different issue and PR.

[github-actions]

Memory usage change @ a2d6ead

Board	flash	%	RAM for global variables	%
arduino:mbed_giga:giga	💚 -64 - 0	-0.0 - 0.0	0 - 0	0.0 - 0.0
arduino:mbed_opta:opta	0 - 0	0.0 - 0.0	0 - 0	0.0 - 0.0
arduino:mbed_portenta:envie_m7	N/A	N/A	N/A	N/A

Click for full report table

Board	examples/DirList flash	%	examples/DirList RAM for global variables	%	examples/FileRead flash	%	examples/FileRead RAM for global variables	%	examples/FileWrite flash	%	examples/FileWrite RAM for global variables	%	examples/OptaDirList flash	%	examples/OptaDirList RAM for global variables	%	examples/PortentaOTA flash	%	examples/PortentaOTA RAM for global variables	%
arduino:mbed_giga:giga	0	0.0	0	0.0	-64	-0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0
arduino:mbed_opta:opta	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0
arduino:mbed_portenta:envie_m7	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A

Click for full report CSV

Board,examples/DirList<br>flash,%,examples/DirList<br>RAM for global variables,%,examples/FileRead<br>flash,%,examples/FileRead<br>RAM for global variables,%,examples/FileWrite<br>flash,%,examples/FileWrite<br>RAM for global variables,%,examples/OptaDirList<br>flash,%,examples/OptaDirList<br>RAM for global variables,%,examples/PortentaOTA<br>flash,%,examples/PortentaOTA<br>RAM for global variables,%
arduino:mbed_giga:giga,0,0.0,0,0.0,-64,-0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0
arduino:mbed_opta:opta,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0
arduino:mbed_portenta:envie_m7,N/A,N/A,N/A,N/A,N/A,N/A,N/A,N/A,N/A,N/A,N/A,N/A,N/A,N/A,N/A,N/A,N/A,N/A,N/A,N/A