arm64: dts: socfpga: swvp: remove phy-addr in the GMAC node

This addresses this warning:
socfpga_stratix10_swvp.dtb: ethernet@ff800000 (altr,socfpga-stmmac-a10-s10):
'phy-addr' does not match any of the regexes: '^pinctrl-[0-9]+$'

Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>

Author: Dinh Nguyen

arch/arm64/boot/dts/altera/socfpga_stratix10_swvp.dts

@@ -68,7 +68,6 @@
 &gmac1 {
 	status = "okay";
 	phy-mode = "rgmii";
-	phy-addr = <0xffffffff>;
 };
 
 &gmac2 {