ARM: dts: stm32: Add missing ETHCK clock to ethernet node on stm32mp1

Add missing 'eth-ck' clock to the ethernet node on stm32mp1. These
clock are used to generate external clock signal for the PHY in case
'st,eth_ref_clk_sel' is specified.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Christophe ROULLIER <christophe.roullier@st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Patrice Chotard <patrice.chotard@st.com>
Cc: Patrick Delaunay <patrick.delaunay@st.com>
Cc: linux-stm32@st-md-mailman.stormreply.com
To: linux-arm-kernel@lists.infradead.org
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>

arch/arm/boot/dts/stm32mp151.dtsi

@@ -1369,10 +1369,12 @@
 			clock-names = "stmmaceth",
 				      "mac-clk-tx",
 				      "mac-clk-rx",
+				      "eth-ck",
 				      "ethstp";
 			clocks = <&rcc ETHMAC>,
 				 <&rcc ETHTX>,
 				 <&rcc ETHRX>,
+				 <&rcc ETHCK_K>,
 				 <&rcc ETHSTP>;
 			st,syscon = <&syscfg 0x4>;
 			snps,mixed-burst;