i.MX8MQ Phanbell board uses Realtek RTL8211FD as Ethernet PHY.
Its datasheet states that the proper post reset duration should be at least 50 ms.

Fixes: f34d4bfa ("arm64: dts: imx8mq-phanbell: Add support for ethernet")
Signed-off-by: Alifer Moraes <alifer.wsdm@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>