carl9170 firmware: command endpoint is bulk in full-speed mode

Roland Wahl discovered that endpoint 4 needs to be an bulk
endpoint in the full-speed configuration.

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
carl9170 firmware: update README.md

New version of the README in markdown. Includes additional
information about contact and firmware configuration.

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>