phy: cadence-torrent: use swap() to make code cleaner

Use the macro 'swap()' defined in 'include/linux/minmax.h' to avoid
opencoding it.

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Yang Guang <yang.guang5@zte.com.cn>
Link: https://lore.kernel.org/r/20211104065233.1833499-1-yang.guang5@zte.com.cn


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