soundwire: qcom: reinit broadcast completion

[ Upstream commit f936fa7a ]

For some reason we never reinit the broadcast completion, there is a
danger that broadcast commands could be treated as completed by driver
from previous complete status.
Fix this by reinitializing the completion before sending a broadcast command.

Fixes: ddea6cf7

 ("soundwire: qcom: update register read/write routine")
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20221026110210.6575-2-srinivas.kandagatla@linaro.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>