phy: renesas: r8a779f0-eth-serdes: Fix register setting

Fix register setting which is typo in r8a779f0_eth_serdes_chan_setting().

Fixes: 74285944

 ("phy: renesas: Add Renesas Ethernet SERDES driver for R-Car S4-8")
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/20221226064216.3895421-1-yoshihiro.shimoda.uh@renesas.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>