Include <sys/soundcard.h> instead of <linux/soundcard.h>

[GitHub pull_request - opened <github@xxxxxxxxxxxxxxxx>]

alsa-project/alsa-oss pull request #3 was opened from davidebeatrici:

The `linux` folder strictly contains kernel headers, including OSSv3's.

A distribution may package the OSS development header(s) separately.

Request URL   : https://github.com/alsa-project/alsa-oss/pull/3
Patch URL     : https://github.com/alsa-project/alsa-oss/pull/3.patch
Repository URL: https://github.com/alsa-project/alsa-oss