ARM: dts: imx6q-dhcom: Fix ethernet reset time properties

Fix ethernet reset time properties as described in
Documentation/devicetree/bindings/net/ethernet-phy.yaml

Fixes: 52c7a088 ("ARM: dts: imx6q: Add support for the DHCOM iMX6 SoM and PDK2")
Signed-off-by: Christoph Niedermaier <cniedermaier@dh-electronics.com>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: Marek Vasut <marex@denx.de>
Cc: NXP Linux Team <linux-imx@nxp.com>
Cc: kernel@dh-electronics.com
To: linux-arm-kernel@lists.infradead.org
Signed-off-by: Shawn Guo <shawnguo@kernel.org>