package/bluez-alsa: fix location of alsa config files

package/bluez-alsa: fix location of alsa config files

Since alsa-lib version 1.1.7 [1] the location for add-on config files
has changed.

In fact, the path for the alsa add-on config files has never been
correct set in the package (it should have been
`/usr/share/alsa/alsa.conf.d`).

With alsa-lib version 1.1.7 or later the correct path is
`/etc/alsa/conf.d`.

[1] https://github.com/alsa-project/alsa-lib/commit/93e03bdc2a3dcd5d12516f5de78e14d88a32ff2c

Signed-off-by: Jörg Krause <joerg.krause@embedded.rocks>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>