net: phy: marvell-88q2xxx: Make register writer function generic

In preparation to adding auto negotiation support to mv88q2110 move and
rename the helper function used to write an array of register values to
the PHY.

Just as for mv88q2220 devices this helper will be needed to for the
initial configuration of the mv88q2110 to support auto negotiation.

The function is moved verbatim, there is no change in behavior.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Dimitri Fedrau <dima.fedrau@gmail.com>
Tested-by: Stefan Eichenberger <eichest@gmail.com>
Link: https://patch.msgid.link/20241005112412.544360-3-niklas.soderlund+renesas@ragnatech.se


Signed-off-by: Jakub Kicinski <kuba@kernel.org>