AVDTP in principle allows 62 endpoints, but in practice it appears some
devices (Samsung Galaxy Buds2 Pro, Redmi Buds 3 Lite, probably others)
fail to connect A2DP when the number is somewhere above 24. A2DP
connection works when initiated from the Central, but not when the
device itself does it, so these devices are not fully broken. We should
reduce the number of registered A2DP endpoints to avoid running into
problems with such broken devices.
Some of our source codecs are the same actual codec with the same
configuration, and don't need separate source endpoints.
Allow codecs to not have a registered endpoint (fill_caps == NULL), and
tolerate codecs with the same endpoint name. In codec switch, keep
track separately which of the codecs with the same endpoint name the
local endpoint is currently associated with.
The codec may need to take into account endpoint preferred QoS values,
so parse this information and pass it to the codec's get_qos.
All the QoS struct values need to be set, as otherwise BlueZ may pass
uninitialized zero values over the air, which devices can reject. This
does not apply to CIG/CIS ids, which are automatically allocated by
default.
Fixes connecting to nrf5340 devkit, which requires a valid TargetLatency
value.
