arm64: dts: mediatek: mt8173-elm: drop PMIC's syscon node

According to AngeloGioacchino Del Regno, the syscon node in PMIC is
neither needed nor used.  It looks like a solution to expose some of the
registers of PMIC.

Drop it to solve also incorrect number of entries in the "reg" property
and fix dtbs_check warning:

  mt8173-elm.dtb: syscon@c000: reg: [[0, 49152], [0, 264]] is too long

Link: https://lore.kernel.org/all/671a4b1e-3d95-438c-beae-d967e0ad1c77@collabora.com/Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240612092421.52917-3-krzysztof.kozlowski@linaro.orgSigned-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

arch/arm64/boot/dts/mediatek/mt8173-elm.dtsi

@@ -1134,12 +1134,6 @@ mt6397_vibr_reg: ldo_vibr {
 		rtc: mt6397rtc {
 			compatible = "mediatek,mt6397-rtc";
 		};
-
-		syscfg_pctl_pmic: syscon@c000 {
-			compatible = "mediatek,mt6397-pctl-pmic-syscfg",
-				     "syscon";
-			reg = <0 0x0000c000 0 0x0108>;
-		};
 	};
 };