audio policy: engine configurable: change default in call routing for line out device

This patch is the counter part of a0b18ce8.
It updates engine configurable conf file accordingly:

It solves:
Current strategy is to use LINE OUT for calls only when speaker phone mode
is enabled.
This creates confusion because most users don't understand why the behavior
differs between a headset and a line out.
Also the main use of a line out device for calls is when connected to a car kit
via an aux cable. In this case, you want to use the car kit by default without
having to touch your phone and select speaker phone.

Bug: Bug: 27548502

Change-Id: I07440fc882573a1ef797f35c86a2ce4ddf1389b1
Signed-off-by: François Gaffie <francois.gaffie@intel.com>