arm64: dts: imx8mp: add clock-cells to hsio-blk-ctrl

The HSIO blk-ctrl exposes the high performance PLL as
a simple clock.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Tested-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Tested-by: Lukas F. Hartmann <lukas@mntre.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mp.dtsi

@@ -1195,6 +1195,7 @@
 						<&noc IMX8MP_ICM_PCIE &noc IMX8MP_ICN_HSIO>;
 				interconnect-names = "noc-pcie", "usb1", "usb2", "pcie";
 				#power-domain-cells = <1>;
+				#clock-cells = <0>;
 			};
 		};