arm: dts: k3-j721e-r5-common-proc-board: Disable power-domains for mcu uart

mcu uart will be used during uart boot for loading sysfw.itb. Since
sysfw is not yet available during uart load, power-domain cannot be
enabled. We need to rely on ROM for doing that, so disable power-domains
and clocks for mcu uart. Also fix the mcu uart frequency.

Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>

arch/arm/dts/k3-j721e-r5-common-proc-board.dts

@@ -157,9 +157,13 @@
 };
 
 &mcu_uart0 {
+	/delete-property/ power-domains;
+	/delete-property/ clocks;
+	/delete-property/ clock-names;
 	pinctrl-names = "default";
 	pinctrl-0 = <&mcu_uart0_pins_default>;
 	status = "okay";
+	clock-frequency = <48000000>;
 };
 
 &main_uart0 {