Bluetooth: Add support for fallback between CVSD recommended settings

When CVSD is requested and eSCO is supported, try to establish eSCO connection
using S3 settings. If it fails, fallback in sequence to S2, S1, D1, D0 settings.
These settings are described in Bluetooth HFP 1.6 specification p. 101.

Signed-off-by: Frédéric Dalleau <frederic.dalleau@linux.intel.com>