Changes

mobile: cosmetic: fix -Wswitch in tch_voice_state_init()

Not really critical, just make gcc happy:

tch_voice.c: In function ‘tch_voice_state_init’:
tch_voice.c:117:9: warning: enumeration value ‘TCH_VOICE_IOH_GAPK’ not handled in switch [-Wswitch]
  117 |         switch (state->handler) {
      |         ^~~~~~

Change-Id: I46afce396f730de26f21e0e4ec71e144aafd6beb