Fix slimbus case being broken thanks to a typo.

Fixes: 5bd77324 ("soundwire: qcom: avoid dependency on CONFIG_SLIMBUS")
Signed-off-by: Jonathan Marek <jonathan@marek.ca>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20200908140818.28373-1-jonathan@marek.caSigned-off-by: Vinod Koul <vkoul@kernel.org>