ARM: dts: imx6qdl-icore-1.5: Remove duplicate phy reset methods

Engicam i.CoreM6 1.5 Quad/Dual MIPI dtsi is reusing fec node
from Engicam i.CoreM6 dtsi but have sampe copy of phy-reset-gpio
and phy-mode properties.

So, drop this phy reset methods from imx6qdl-icore-1.5 dsti file.

Cc: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Tested-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>