ALSA: ua101: Replace tasklet with work

The tasklet is an old API that should be deprecated, usually can be
converted to another decent API.  In UA101 driver, a tasklet is still
used for handling the output URBs.  It can be achieved gracefully with
a work queued in the high-prio system workqueue, too.

This patch replaces the tasklet usage in UA101 driver with a simple
work.

Link: https://lore.kernel.org/r/20200903104131.21097-5-tiwai@suse.de


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