added default case to avoid compiler warnings of unhandled (library-private) enum values
added default case
to avoid compiler warnings of unhandled (library-private) enum values

This avoids the compiler warning "enumeration value ‘SND_PCM_STATE_PRIVATE1’ not handled
in switch [-Wswitch]"

This library-private PCM state is used internally only (see
https://www.alsa-project.org/alsa-doc/alsa-lib/group___p_c_m.html#ga61ac499cb3701ce536d4d83725908860).

i-rinat/apulse,i-rinat/apulse