- fix warnings build hcd max3421 with rp2040
- add tinyusb_host_max3421 target for rp2040 cmake, -DMAX3421_HOST=1
will enable this
- add max3421 driver implementation for rp2040 family
- update tusb_config for host to allow easy enable host selection for
rp2040 (default/pio-usb/max3421)
- previously CFG_TUH_HID is max number of interfaces per device which is
rather limited and consume more resources than needed.
- change hid host instance in API to index
IAR generates warning Pe111 'statement is unreachable'. In a couple of
cases, replace return statements with TU_ATTR_FALLTHROUGH; because some
compilers apparently can't figure out that the return statements are
unreachable but do whinge about an imagined fall-through without them!
