From: Moritz Fischer <mdf@kernel.org>
Date: Fri, 31 Aug 2018 13:30:54 -0700

Fix Kconfig warning with OF_MDIO where OF_MDIO was
selected unconditionally instead of only when
OF is actually enabled.

Fixes 7e8d5755be0e ("net: nixge: Add support for 64-bit platforms")
Suggested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Moritz Fischer <mdf@kernel.org>

Applied, thanks.