aci: don't reset audio volume on AT+CFUN TI's AT-command-controlled modems have always had the peculiar misfeature where the audio volume gets reset to default on AT+CFUN, blowing away any AT+CLVL changes made previously. This misfeature is now getting worse, now that the audio volume may be set as a side effect of audio mode loading, in addition to explicit AT+CLVL. So let's take out this unnecessary audio volume reset.

# modem services config: voice only
GPRS=0
SRVC=0

# this is a phone handset config
MMI=2
R2D_STATE=1

# small B&W UI version on 96x64 pixel B&W R2D framebuffer
R2D_EMBEDDED_LCD=10
UI_CONFIG=smallbw