dts: Introduce shared binding for nxp flexcomm peripheral

The flexcomm peripheral on lpc socs can be configured into uart, spi,
i2c, or i2s mode. Introduce a shared device tree binding that gets
included by the more specific driver type bindings.

Signed-off-by: Maureen Helm <maureen.helm@nxp.com>

dts/bindings/arm/nxp,lpc-flexcomm.yaml

@@ -0,0 +1,15 @@
+# Copyright (c) 2020 NXP
+# SPDX-License-Identifier: Apache-2.0
+
+description: LPC Flexcomm node
+
+compatible: "nxp,lpc-flexcomm"
+
+include: base.yaml
+
+properties:
+    reg:
+      required: true
+
+    interrupts:
+      required: true

dts/bindings/i2c/nxp,lpc-i2c.yaml

@@ -5,11 +5,4 @@ description: LPC I2C node
 
 compatible: "nxp,lpc-i2c"
 
-include: i2c-controller.yaml
-
-properties:
-    reg:
-      required: true
-
-    interrupts:
-      required: true
+include: [i2c-controller.yaml, "nxp,lpc-flexcomm.yaml"]

dts/bindings/serial/nxp,lpc-usart.yaml

@@ -5,11 +5,4 @@ description: LPC USART
 
 compatible: "nxp,lpc-usart"
 
-include: uart-controller.yaml
-
-properties:
-    reg:
-      required: true
-
-    interrupts:
-      required: true
+include: [uart-controller.yaml, "nxp,lpc-flexcomm.yaml"]

dts/bindings/spi/nxp,lpc-spi.yaml

@@ -5,11 +5,4 @@ description: NXP LPC SPI controller
 
 compatible: "nxp,lpc-spi"
 
-include: spi-controller.yaml
-
-properties:
-    reg:
-      required: true
-
-    interrupts:
-      required: true
+include: [spi-controller.yaml, "nxp,lpc-flexcomm.yaml"]