Add change buffer length option

Add change buffer length option

Some samples were lost in userspace because the FIFO
size was 2 and sometimes they were overwritten before
they were read.
The buffer length is now configurable from HALD using
system prop and the default value is increased to 16.

Tracked-On: https://jira01.devtools.intel.com/browse/GMINL-13814
Change-Id: I7aed65942005fb14691a4239cd3e389b53037208
Signed-off-by: Irina Patru <irina.patru@intel.com>
Reviewed-on: https://android.intel.com:443/391412