soundwire: Use min() to improve code

Use min() to reduce the code in qcom_swrm_xfer_msg() and improve its
readability.

Signed-off-by: Qianfeng Rong <rongqianfeng@vivo.com>
Link: https://lore.kernel.org/r/20250814142428.282639-1-rongqianfeng@vivo.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>