Permit slashes in soundcard description

Cuttlefish recently switched to virtio-snd, which presents itself like
this in /proc/asound/cards:

 0 [SoundCard      ]: virtio-snd - VirtIO SoundCard
                      VirtIO SoundCard at pci/0000:00:16.0/virtio21

Our test for this proc file didn't account for the description field
having forward slashes, leading to parser errors. Fix it.

Bug: 198461504
Change-Id: I498114fa0e4c010dab5dd6c6e8d28e414c1ab6fc
1 file changed