Documentation: DT: Add entries for BCM3384 and its peripherals

This covers the new "brcm,*" devices added in the upcoming bcm3384 commit.
Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Cc: f.fainelli@gmail.com
Cc: mbizon@freebox.fr
Cc: jogo@openwrt.org
Cc: jfraser@broadcom.com
Cc: linux-mips@linux-mips.org
Cc: devicetree@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/8168/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Documentation/devicetree/bindings/mips/brcm/bcm3384-intc.txt

+* Interrupt Controller
+
+Properties:
+- compatible: "brcm,bcm3384-intc"
+
+  Compatibility with BCM3384 and possibly other BCM33xx/BCM63xx SoCs.
+
+- reg: Address/length pairs for each mask/status register set.  Length must
+  be 8.  If multiple register sets are specified, the first set will
+  handle IRQ offsets 0..31, the second set 32..63, and so on.
+
+- interrupt-controller: This is an interrupt controller.
+
+- #interrupt-cells: Must be <1>.  Just a simple IRQ offset; no level/edge
+  or polarity configuration is possible with this controller.
+
+- interrupt-parent: This controller is cascaded from a MIPS CPU HW IRQ, or
+  from another INTC.
+
+- interrupts: The IRQ on the parent controller.
+
+Example:
+	periph_intc: periph_intc@14e00038 {
+		compatible = "brcm,bcm3384-intc";
+
+		/*
+		 * IRQs 0..31:  mask reg 0x14e00038, status reg 0x14e0003c
+		 * IRQs 32..63: mask reg 0x14e00340, status reg 0x14e00344
+		 */
+		reg = <0x14e00038 0x8 0x14e00340 0x8>;
+
+		interrupt-controller;
+		#interrupt-cells = <1>;
+
+		interrupt-parent = <&cpu_intc>;
+		interrupts = <4>;
+	};

Documentation/devicetree/bindings/mips/brcm/bmips.txt

+* Broadcom MIPS (BMIPS) CPUs
+
+Required properties:
+- compatible: "brcm,bmips3300", "brcm,bmips4350", "brcm,bmips4380",
+  "brcm,bmips5000"
+
+- mips-hpt-frequency: This is common to all CPUs in the system so it lives
+  under the "cpus" node.

Documentation/devicetree/bindings/mips/brcm/cm-dsl.txt

+* Broadcom cable/DSL platforms
+
+SoCs:
+
+Required properties:
+- compatible: "brcm,bcm3384", "brcm,bcm33843"
+
+Boards:
+
+Required properties:
+- compatible: "brcm,bcm93384wvg"

Documentation/devicetree/bindings/mips/brcm/usb.txt

+* Broadcom USB controllers
+
+Required properties:
+- compatible: "brcm,bcm3384-ohci", "brcm,bcm3384-ehci"
+
+  These currently use the generic-ohci and generic-ehci drivers.  On some
+  systems, special handling may be needed in the following cases:
+
+  - Restoring state after systemwide power save modes
+  - Sharing PHYs with the USBD (UDC) hardware
+  - Figuring out which controllers are disabled on ASIC bondout variants