Add support for mapping C22 register access to C45-only PHYs.
This is mainly useful for 'mii info' command, which performs
C22 only access to determine PHY ID and link state and does
not work well with this driver so far.
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
(cherry picked from commit 678f7c8f56)