4a-alsa-core: bump to latest revision

4a-alsa-core: bump to latest revision

Also add a new dependency to 'libafb-helpers' from
the included changes.

Included changes:
* 9b71be0 Improve tests for 4a-alsa-core
* b8af262 Rework ALSA card get info function
* 4eb02cc Rework ALSA control set/get function
* b04cb5e Improve prints when setting values of control
* 056aa12 Send back cardid only if request is valid
* 0219aa9 Improve ALSA control creation
* 980a8f0 Fix dbScale generation when adding custom control

BUG-AGL: SPEC-2435

Change-Id: I4e9a7f91be98ad157899ed864ae47f2c383514dd
Signed-off-by: Jonathan Aillet <jonathan.aillet@iot.bzh>