ARM: dts: dra7-evm: Add wilink8 wlan support

The wilink module is a combo wireless connectivity sdio
card based on Texas Instrument's wl18xx solution. It is a
4-wire, 1.8V, embedded sdio wlan device with an external
irq line and is power-controlled by a gpio-based fixed
regulator.

Add pinmux configuration and IODelay values for MMC4.
On dra7-evm, MMC4 is used for connecting to wilink module.

IODelay data credits to :  Vishal Mahaveer <vishalm@ti.com>
and Sekhar Nori <nsekhar@ti.com>

Signed-off-by: Ido Yariv <ido@wizery.com>
Signed-off-by: Eyal Reizer <eyalr@ti.com>
Signed-off-by: Hari Nagalla <hnagalla@ti.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/boot/dts/dra7-evm-common.dtsi

@@ -260,3 +260,18 @@
 &pcie1_rc {
 	status = "okay";
 };
+
+&mmc4 {
+	bus-width = <4>;
+	cap-power-off-card;
+	keep-power-in-suspend;
+	non-removable;
+	#address-cells = <1>;
+	#size-cells = <0>;
+	wifi@2 {
+		compatible = "ti,wl1835";
+		reg = <2>;
+		interrupt-parent = <&gpio5>;
+		interrupts = <7 IRQ_TYPE_EDGE_RISING>;
+	};
+};