arm64: dts: cavium: thunder2-99xx: drop redundant reg-names

There is no "reg-names" property in the PCI bindings and the value does
not conform to Devicetree coding style (upper-case letters, space), so
assume this was copied from downstream.

This fixes dtbs_check warning:

  thunder2-99xx.dtb: pcie@30000000: Unevaluated properties are not allowed ('reg-names' was unexpected)

Link: https://lore.kernel.org/r/20240407102841.38617-1-krzysztof.kozlowski@linaro.orgSigned-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

arch/arm64/boot/dts/cavium/thunder2-99xx.dtsi

@@ -103,7 +103,6 @@ pcie@30000000 {
 
 		/* ECAM at 0x3000_0000 - 0x4000_0000 */
 		reg = <0x0 0x30000000  0x0 0x10000000>;
-		reg-names = "PCI ECAM";
 
 		/*
 		 * PCI ranges: