icE1usb fw: Use the interface/endpoints #define in usb_e1.c

Avoid hardcoded ids everywhere. This also prepares a bit for
multi-port support in the future.

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
Change-Id: I89c86ac6afd52dd19e3383b38c3311276a090d50
1 file changed