ARM: dts: imx6qdl: move phy properties into phy device node

This patch fixes issues found by dtbs_check:
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- dtbs_check DT_SCHEMA_FILES=Documentation/devicetree/bindings/net/fsl,fec.yaml

According to the Micrel PHY dt-binding:
Documentation/devicetree/bindings/net/micrel-ksz90x1.txt,
Add clock delay in an Ethernet OF device node is deprecated, so move
these properties to PHY OF device node.

Suggested-by: Rob Herring <robh@kernel.org>
Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>