sndif: Add explicit back and front parameter negotiation
In order to provide explicit stream parameter negotiation between
backend and frontend the following changes are introduced in the protocol:
add XENSND_OP_HW_PARAM_QUERY request to read/update
configuration space for the parameter given: request passes
desired parameter interval (mask) and the response to this request
returns min/max interval (mask) for the parameter to be used.
Parameters supported by this request/response:
- format mask
- sample rate interval
- number of channels interval
- buffer size, interval, frames
- period size, interval, frames