The original code switched ADC clock source depending on required
prescaler. Maybe thats possible on K64, but on K22 it just tried to set
clock to non-existing source. Not it gets a bit above MAX_ADC, but that
is set fairly conservative so is not an issue.
This commit fixes a number of issues with invalid/wrong pin assignments for the
KL25Z mbed target:
- analog: PTC1 doesn't seem to be exported at all, replaced with PTC2.
- digitalin/out, interruptin, portin/out: these tests used PTA1 and PTA2, which
are the console UART pins for the KL25Z mbed. The tests now use PTA4<->PTC5 and
PTA5<->PTC6.