There are a maximum of 8 USB endpoints and each has 2 buffer slots
(in/out). This commit add support for up to 8 endpoints and adds FIFO
configuration for USB profiles with 2xVCP on MCUs that have device-only USB
peripherals.
Tested on NUCLEO_WB55 in 2xVCP, 2xVCP+MSC and 2xVCP+MSC+HID mode.
Signed-off-by: Damien George <damien@micropython.org>