airoha: an7581: 6.18: switch to kmod-phy-realtek for w1700k
Use the new kmod-phy-realtek driver for kernel 6.18 on
Gemtek W1700K.
The driver selection is gated using `KERNEL_PATCHVER` to
avoid build failures on 6.12.
The device tree selection is also gated by `KERNEL_PATCHVER`
to select the appropriate device tree per kernel version.
Once kernel 6.18 is tested stable for airoha these changes
can be simplified and the obsolete properties removed.
Signed-off-by: Kenneth Kasilag <kenneth@kasilag.me>
Link: https://github.com/openwrt/openwrt/pull/21019
Signed-off-by: Jonas Jelonek <jelonek.jonas@gmail.com>