of/mdio: Staticise !CONFIG_OF stubs
of/mdio: Staticise !CONFIG_OF stubs

The !CONFIG_OF stubs aren't static so if multiple files include the
header with this configuration then the linker will see multiple
definitions of the stubs.

Reported-by: Fengguang Wu <24f7fe9d205c8a9f6ade0c2894e14303ca16087f@intel.com>
Signed-off-by: Mark Brown <b51b9a92386687a9ac927cebfa0f978adeb8cea5@opensource.wolfsonmicro.com>
Acked-by: Thomas Petazzoni <a5d87d2bd7c424ee5cbdb4e978635bf653d5a005@free-electrons.com>
Acked-by: Srinivas Kandagatla <e9a3fcd7365f8e6a430ada3b68b984cb4aaf0c3e@st.com>
Signed-off-by: David S. Miller <fe08d3c717adf2ae63592e4c9aec6e3e404d8e3e@davemloft.net>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas