PCI: tegra: Convert to devm_of_phy_optional_get()

Use the new devm_of_phy_optional_get() helper instead of open-coding the
same operation.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/56508eeadf7fa8692877e872871f10294d48c49d.1674584626.git.geert+renesas@glider.be


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