net: stmmac: rk: convert rk3588 to mask-based interface mode config

net: stmmac: rk: convert rk3588 to mask-based interface mode config

rk3588 has a quirk compared to the other Rockchip implementations in
that the interface mode configuration register is in the php_grf
regmap rather than the grf regmap. Add a flag to indicate this, and
a separate function to write to the appropriate regmap. This allows
rk3588 to be converted.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1vmqmm-00000007VCP-2XZc@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>