ARM: shmobile: ape6evm: Fix LAN9220 VDDVARIO voltage

The LAN9220 VDDVARIO supply is powered by a 1.8V source, not 3.3V. Fix
it in the device tree.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>