HDA driver: use optional settings file

Patch by Pete Goodeve, ticket #9134.
(Removed play_sample_rate and record_sample_rate as suggested in
patch review, adjusted hda.settings accordingly.)

Tune buffer size and buffer count with an optional settings file
/boot/home/config/settings/kernel/drivers/hda.settings. Same as
it's done for the auich driver.

Pete:
> I [...] request 4 buffers of 1024 frames, I get a nice 13-14ms latency.

Change-Id: I3c1c64375d22b525afb970d5e8379b22b8514438
Reviewed-on: https://review.haiku-os.org/521
Reviewed-by: Jérôme Duval <jerome.duval@gmail.com>