This commit switches the STM32WB HCI interface (between the two CPUs) to
require the use of MICROPY_PY_BLUETOOTH_USE_SYNC_EVENTS, and as a
consequence to require NimBLE. IPCC RX IRQs now schedule the NimBLE
handler to run via mp_sched_schedule.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>