staging: wilc1000: updated DT binding documentation

Merged the DT binding documentation of SDIO and SPI into a single file.
Removed documentation for some of the properties which are not required
and handled review comments received in [1] & [2].

[1]. https://lore.kernel.org/linux-wireless/20200303020230.GA15543@bogus
[2]. https://lore.kernel.org/linux-wireless/20200303015558.GA6876@bogus

Signed-off-by: Ajay Singh <ajay.kathat@microchip.com>
Link: https://lore.kernel.org/r/20200307085523.7320-4-ajay.kathat@microchip.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: ajaykathat

drivers/staging/wilc1000/microchip,wilc1000,sdio.yaml

@@ -0,0 +1,72 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/net/wireless/microchip,wilc1000.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Microchip WILC wireless devicetree bindings
+
+maintainers:
+  - Adham Abozaeid <adham.abozaeid@microchip.com>
+  - Ajay Singh <ajay.kathat@microchip.com>
+
+description:
+  The wilc1000 chips can be connected via SPI or SDIO. This document
+  describes the binding to connect wilc devices.
+
+properties:
+  compatible:
+    const: microchip,wilc1000
+
+  spi-max-frequency: true
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    description: phandle to the clock connected on rtc clock line.
+    maxItems: 1
+
+  clock-names:
+    const: rtc
+
+required:
+  - compatible
+  - interrupts
+
+examples:
+  - |
+    spi1: spi@fc018000 {
+      #address-cells = <1>;
+      #size-cells = <0>;
+      cs-gpios = <&pioB 21 0>;
+      wifi@0 {
+        compatible = "microchip,wilc1000";
+        spi-max-frequency = <48000000>;
+        reg = <0>;
+        interrupt-parent = <&pioC>;
+        interrupts = <27 0>;
+        clocks = <&pck1>;
+        clock-names = "rtc";
+      };
+    };
+
+  - |
+    mmc1: mmc@fc000000 {
+      #address-cells = <1>;
+      #size-cells = <0>;
+      pinctrl-names = "default";
+      pinctrl-0 = <&pinctrl_mmc1_clk_cmd_dat0 &pinctrl_mmc1_dat1_3>;
+      non-removable;
+      vmmc-supply = <&vcc_mmc1_reg>;
+      vqmmc-supply = <&vcc_3v3_reg>;
+      bus-width = <4>;
+      wifi@0 {
+        compatible = "microchip,wilc1000";
+        reg = <0>;
+        interrupt-parent = <&pioC>;
+        interrupts = <27 0>;
+        clocks = <&pck1>;
+        clock-names = "rtc";
+      };
+    };