Revert "Alsa: fix crash when detecting devices."

Revert "Alsa: fix crash when detecting devices."

This reverts commit 0ab81ef59f35d103ec8174834c4fc2a4dcced453.
The workaround causes software devices not to appear in the list
of available devices. Besides, since the crash is caused by a bug
in older versions of Alsa, the workaround was probably a bad idea
in the first place. People should update Alsa instead.

Task-number: QTBUG-42326
Change-Id: I37923a87180d1c5abc18d52d84f633e14ba46860
Reviewed-by: Christian Stromme <christian.stromme@theqtcompany.com>