Add r8a779f0_eth_serdes_exit() to clear the initialized flag
for re-initializing this PHY if needed.
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/20231011081817.257113-3-yoshihiro.shimoda.uh@renesas.comSigned-off-by: Vinod Koul <vkoul@kernel.org>