[audio][hda] Update HDA driver to use interrupt event sources.

Use new interrupt event sources from dispatcher pool. This removes
what should be the last instance of manually signalling physical
interrupt handles in the system. This should allow for progress on
ZX-2177.

ZX-2177 #comment Last use of manual interrupt signaling removed.
Test: Manual on NUC; ran audio tone test for 24 hrs.

Change-Id: I0c1e0f8f9fe5731b03f0545a7d241f7f0676bf75

[dev][intel-hda] Remove duplicated copy of thread_annotations.h

This copy was left over from when the driver lived in a separate Git
repo.

Use the header system/private/zircon/thread_annotations.h instead.

Change-Id: If4f8de94eed8a06340bde221bf199ba2cbb0f13c

[zx] Move public zx headers to match naming convention

The zx library provides headers intended for general use, so the
include path should be spelled <lib/zx/foo.h> as per
https://fuchsia.googlesource.com/docs/+/master/development/languages/c-cpp/naming.md.
This moves the headers into the proper location and updates includes to
match.

Change-Id: I6fc9b2a491b5f8b0d270c4dfc77fa4be5739071b

[audio][hda] Update Intel HDA driver logging.

Update the Intel HDA driver's logging to use zxlogf instead of printf.

Change-Id: Ice8ef22e7ae48da566b16fbb705a6a3d148f2d6c

[dev][intel-hda] Add intel-hda audio drivers to zircon build

Change-Id: I098eb734b5dfef5a267d07db67860fff04014486

[dev][audio] Move //drivers/audio project to zircon

Change-Id: I5b60b0134a9d2d788922244b81401bc55d9837e8