kernel: let kmod-rtl8366-smi conditionally depend on kmod-of-mdio

kernel: let kmod-rtl8366-smi conditionally depend on kmod-of-mdio

We cannot depend on CONFIG_OF in the module definition context as this symbol
is not defined for OpenWrt menuconfig. Depend on the targets that appear to
need the kmod-of-mdio module instead.

The target dependency list may not be complete, it is based on the build
failures encountered by the build bots.

Fixes: dc629d9cf5 ("kernel: fix kmod-switch-rtl8366-smi dependency")
Signed-off-by: Jo-Philipp Wich <jo@mein.io>