ARM: dts: aspeed: Add KCS support for LPC BMC

This adds the description of the four Keyboard Controller Style (KCS)
IPMI communication channels present in the ASPEED BMC. They are disabled
by default.
Signed-off-by: Vijay Khemka <vijaykhemka@fb.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>

arch/arm/boot/dts/aspeed-g5.dtsi

@@ -331,8 +331,32 @@ lpc: lpc@1e789000 {
 				ranges = <0x0 0x1e789000 0x1000>;
 
 				lpc_bmc: lpc-bmc@0 {
-					compatible = "aspeed,ast2500-lpc-bmc";
+					compatible = "aspeed,ast2500-lpc-bmc", "simple-mfd", "syscon";
 					reg = <0x0 0x80>;
+					reg-io-width = <4>;
+
+					#address-cells = <1>;
+					#size-cells = <1>;
+					ranges = <0x0 0x0 0x80>;
+
+					kcs1: kcs1@0 {
+						compatible = "aspeed,ast2500-kcs-bmc";
+						interrupts = <8>;
+						kcs_chan = <1>;
+						status = "disabled";
+					};
+					kcs2: kcs2@0 {
+						compatible = "aspeed,ast2500-kcs-bmc";
+						interrupts = <8>;
+						kcs_chan = <2>;
+						status = "disabled";
+					};
+					kcs3: kcs3@0 {
+						compatible = "aspeed,ast2500-kcs-bmc";
+						interrupts = <8>;
+						kcs_chan = <3>;
+						status = "disabled";
+					};
 				};
 
 				lpc_host: lpc-host@80 {
@@ -344,6 +368,13 @@ lpc_host: lpc-host@80 {
 					#size-cells = <1>;
 					ranges = <0x0 0x80 0x1e0>;
 
+					kcs4: kcs4@0 {
+						compatible = "aspeed,ast2500-kcs-bmc";
+						interrupts = <8>;
+						kcs_chan = <4>;
+						status = "disabled";
+					};
+
 					lpc_ctrl: lpc-ctrl@0 {
 						compatible = "aspeed,ast2500-lpc-ctrl";
 						reg = <0x0 0x80>;