Revert "ARM: dts: imx6qdl: enable FEC magic-packet feature"

As 456062b3 ("ARM: imx: add FEC sleep mode callback function") has been
reverted, also revert the dts part.

This reverts commit 07b4d2dd

 ("ARM: dts: imx6qdl: enable FEC
magic-packet feature").

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>