phy: Add devm_of_phy_optional_get() helper

Add an optional variant of devm_of_phy_get() that also takes care of
printing real errors, so drivers no longer have to open-code this
operation.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/4cd0069bcff424ffc5c3a102397c02370b91985b.1674584626.git.geert+renesas@glider.be


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