alsa-mixer: Add "Line Out Jack" to analog-output.conf

alsa-mixer: Add "Line Out Jack" to analog-output.conf

A stationary computer usually has headphone jack(s) and line out jacks.
In some cases analog-output.conf will be a subset of
analog-output-headphones.conf, causing line outs to be unusable (because
headphones are unplugged).

This late in the cycle, this was the safest way I could think of to try
to fix this for a particular computer. In later versions of PulseAudio
we could consider making a dedicated line out path instead, and have
proper jack detection there.

Signed-off-by: David Henningsson <david.henningsson@canonical.com>