namehint: Fix the listing without device number

namehint: Fix the listing without device number

The current code of snd_device_name_hint() has a bug when listing up
devices without the device index (e.g. ctl).  Because it assigns the
default device index 0 unconditionally and it has a check at the later
point to filter entries with dev >= 0, it ended up with empty
outputs.

The fix is simply to remove the bogus assignment of dev = 0.

Signed-off-by: Takashi Iwai <tiwai@suse.de>