arm: dts: k3-j721e-common-proc-board: Mark main_uart0 as shared device

Main uart0 is used as debug console by both R5SPL and A72 bootloader and
Linux. So mark it as shared device so that power-domain request is
successful by both cores.

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

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

@@ -31,6 +31,10 @@
 	status = "disabled";
 };
 
+&main_uart0 {
+	power-domains = <&k3_pds 146 TI_SCI_PD_SHARED>;
+};
+
 &main_uart3 {
 	/* UART not brought out */
 	status = "disabled";