hal: Provide support to enable/disable EC/NS in BT

Currently during a SCO connection ECNS module in ADSP
is disabled by default. Some BT headsets have built-in
support for echo cancellation and noise reduction and
therefore do not require the same to be done again.
Select BT_SCO devices with ECNS modules enabled when
setParameters() is called with NREC=on.

Change-Id: I8bc37358a4510de7112d5247efbd5d3d7420fe43