During production it is often desirable for devices to perform
some kind of basic self-test to isolate defects.
For this it is necessary for the initialization not to hang if a
component is faulty / not connected.
This moves an already exising self-test that was previously enabled
as a debug option to an independent compile-time configurable.
It is necessary to call this in _init() before mrf24j40_hardware_reset()
as the reset function uses xtimer_usleep() which will cause another
thread to get scheduled.
If this thread (e.g. rpl or ipv6) then tries to access the netdev, RIOT
will crash.
The MRF24J40MC/MD/ME modules contain an external power amplifier &
low noise amplifier that has to be enabled manually by setting three bits
in the TESTMODE register.
On MRF24J40MC the power amplifier is powered by a separate voltage regualtor
that has to be enabled by setting GPIO3 to HIGH.
During Sleep and CCA the PA should be disabled.
Co-authored-by: Carton <joel.carron@eeproperty.ch>
Co-authored-by: Benjamin Valentin <benjamin.valentin@ml-pa.com>
