arm64: dts: allwinner: Pine H64: correctly remove reg_gmac_3v3

arm64: dts: allwinner: Pine H64: correctly remove reg_gmac_3v3

There is no "reg_gmac_3v3" device node in sun50i-h6-pine-h64.dts,
although there is "gmac-3v3" with "reg_gmac_3v3" label, so let's assume
author wanted to remove that node.  Delete node via phandle, not via
full node path, to fix this.

Fixes: f33a91175029 ("arm64: dts: allwinner: add pineh64 model B")
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Link: https://lore.kernel.org/r/20240317184130.157695-1-krzysztof.kozlowski@linaro.org
Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>