arm64: dts: imx8-apalis-v1.1: Fix Ethernet PHY reset-names

Per ethernet-phy.yaml, the expected value for the 'reset-names'
property is "phy".

Change it accordingly to fix the following schema warning:

imx8qm-apalis-ixora-v1.1.dtb: ethernet-phy@7: reset-names:0: 'phy' was expected
from schema $id: http://devicetree.org/schemas/net/ethernet-phy.yaml#



Signed-off-by: Fabio Estevam <festevam@denx.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>