boards: st: n6: use ic3 as xspi kernel clock

Configure and enable IC3 to 400MHz and use it as kernel clock for XSPI
instances.

Signed-off-by: Guillaume Gautier <[email protected]>

Author: gautierg-st

boards/st/nucleo_n657x0_q/nucleo_n657x0_q_common.dtsi

@@ -97,6 +97,12 @@
 	status = "okay";
 };
 
+&ic3 {
+	pll-src = <1>;
+	ic-div = <6>;
+	status = "okay";
+};
+
 &ic6 {
 	pll-src = <3>;
 	ic-div = <2>;
@@ -224,6 +230,9 @@ zephyr_udc0: &usbotg_hs1 {
 		     &xspim_p2_io3_pn5 &xspim_p2_io4_pn8 &xspim_p2_io5_pn9
 		     &xspim_p2_io6_pn10 &xspim_p2_io7_pn11>;
 	pinctrl-names = "default";
+	clocks = <&rcc STM32_CLOCK(AHB5, 12)>,
+		 <&rcc STM32_SRC_IC3 XSPI1_SEL(2)>,
+		 <&rcc STM32_CLOCK(AHB5, 13)>;
 	status = "okay";
 
 	mx25um51245g: ospi-nor-flash@70000000 {

boards/st/stm32n6570_dk/stm32n6570_dk_common.dtsi

@@ -107,6 +107,12 @@
 	status = "okay";
 };
 
+&ic3 {
+	pll-src = <1>;
+	ic-div = <6>;
+	status = "okay";
+};
+
 &ic4 {
 	pll-src = <2>;
 	ic-div = <32>;
@@ -238,6 +244,9 @@ zephyr_udc0: &usbotg_hs1 {
 		     &xspim_p1_io12_pp12 &xspim_p1_io13_pp13 &xspim_p1_io14_pp14
 		     &xspim_p1_io15_pp15>;
 	pinctrl-names = "default";
+	clocks = <&rcc STM32_CLOCK(AHB5, 5)>,
+		 <&rcc STM32_SRC_IC3 XSPI1_SEL(2)>,
+		 <&rcc STM32_CLOCK(AHB5, 13)>;
 	status = "okay";
 
 	memc: aps256xxn_obr: memory@90000000 {
@@ -258,6 +267,9 @@ zephyr_udc0: &usbotg_hs1 {
 		     &xspim_p2_io3_pn5 &xspim_p2_io4_pn8 &xspim_p2_io5_pn9
 		     &xspim_p2_io6_pn10 &xspim_p2_io7_pn11>;
 	pinctrl-names = "default";
+	clocks = <&rcc STM32_CLOCK(AHB5, 12)>,
+		 <&rcc STM32_SRC_IC3 XSPI1_SEL(2)>,
+		 <&rcc STM32_CLOCK(AHB5, 13)>;
 	status = "okay";
 
 	mx66uw1g45g: ospi-nor-flash@70000000 {