doc/sequence_charts: fix naming of mncc_fsm to mncc_call

mncc_fsm.[hc] were renamed to mncc_call.[hc] during patch review, which failed
to carry through to this sequence chart.

Also fix the MNCC_ST_* to MNCC_CALL_ST_* and MNCC_EV_* to MNCC_CALL_EV_*.

Change-Id: I03ee1b43ab95dca3c43fdb9e92dc158aad5a4203
2 files changed