Simplify Alsa backend
Simplify Alsa backend

Use only one regexp for both values.
Remove check that perc is an int since it satisfies '\d{2,3}' already.

docwalter/py3status,guiniol/py3status,tobes/py3status,guiniol/py3status,ultrabug/py3status,Andrwe/py3status,Andrwe/py3status,vvoland/py3status,ultrabug/py3status,ultrabug/py3status,tobes/py3status,valdur55/py3status,valdur55/py3status,valdur55/py3status,alexoneill/py3status