phy: Use of_node_name_eq for node name comparisons

Convert string compares of DT node names to use of_node_name_eq helper
instead. This removes direct access to the node name pointer.

For instances using of_node_cmp, this has the side effect of now using
case sensitive comparisons. This should not matter for any FDT based
system which all of these are.

Cc: Kishon Vijay Abraham I <kishon@ti.com>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-rockchip@lists.infradead.org
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>