ASoC: wsa881x: Assign device number in reset

Assign the logical device number in the
swr_reset function so that the dev_num of
the speaker device is assigned to the
correct one after a reset event.

CRs-fixed: 2039206
Change-Id: Ief3c65c3b36c93e7dcf775413e527e92d9ec7b0c
Signed-off-by: Karthikeyan Mani <kmani@codeaurora.org>