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.