[PATCH] ARM: dts: stm32: Add PTP clock to Ethernet controller

Add the PTP clock to the Ethernet controller. Otherwise, the driver uses the
main clock to derive the PTP frequency which is not necessarily the correct one.

Tested with linuxptp on Olimex STMP1-OLinuXino-LIME2.

Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
---
  arch/arm/boot/dts/stm32mp151.dtsi | 2 ++
  1 file changed, 2 insertions(+)

diff --git a/arch/arm/boot/dts/stm32mp151.dtsi b/arch/arm/boot/dts/stm32mp151.dtsi
index 3c75abacb374..d1f596ea2fd5 100644
--- a/arch/arm/boot/dts/stm32mp151.dtsi
+++ b/arch/arm/boot/dts/stm32mp151.dtsi

@@ -1421,11 +1421,13 @@
  				      "mac-clk-tx",
  				      "mac-clk-rx",
  				      "eth-ck",
+				      "ptp_ref",
  				      "ethstp";
  			clocks = <&rcc ETHMAC>,
  				 <&rcc ETHTX>,
  				 <&rcc ETHRX>,
  				 <&rcc ETHCK_K>,
+				 <&rcc ETHPTP_K>,
  				 <&rcc ETHSTP>;
  			st,syscon = <&syscfg 0x4>;
  			snps,mixed-burst;