bcm53xx: add DT patch describing pins mux controller

It's needed to support new devices that use specific pin functions.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>

target/linux/bcm53xx/patches-4.14/131-ARM-dts-BCM5301X-Describe-Northstar-pins-mux-control.patch

@@ -0,0 +1,73 @@
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
+Date: Fri, 9 Nov 2018 09:53:56 +0100
+Subject: [PATCH] ARM: dts: BCM5301X: Describe Northstar pins mux controller
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+This describes hardware & will allow referencing pin functions. The
+first usage is UART1 which allows supporting devices using it.
+
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+---
+
+--- a/arch/arm/boot/dts/bcm5301x.dtsi
++++ b/arch/arm/boot/dts/bcm5301x.dtsi
+@@ -37,6 +37,8 @@
+ 			reg = <0x0400 0x100>;
+ 			interrupts = <GIC_SPI 85 IRQ_TYPE_LEVEL_HIGH>;
+ 			clocks = <&iprocslow>;
++			pinctrl-names = "default";
++			pinctrl-0 = <&pinmux_uart1>;
+ 			status = "disabled";
+ 		};
+ 	};
+@@ -391,6 +393,48 @@
+ 		status = "disabled";
+ 	};
+ 
++	dmu@1800c000 {
++		compatible = "simple-bus";
++		ranges = <0 0x1800c000 0x1000>;
++		#address-cells = <1>;
++		#size-cells = <1>;
++
++		cru@100 {
++			compatible = "simple-bus";
++			reg = <0x100 0x1a4>;
++			ranges;
++			#address-cells = <1>;
++			#size-cells = <1>;
++
++			pin-controller@1c0 {
++				compatible = "brcm,bcm4708-pinmux";
++				reg = <0x1c0 0x24>;
++				reg-names = "cru_gpio_control";
++
++				spi-pins {
++					groups = "spi_grp";
++					function = "spi";
++				};
++
++				i2c {
++					groups = "i2c_grp";
++					function = "i2c";
++				};
++
++				pwm {
++					groups = "pwm0_grp", "pwm1_grp",
++						 "pwm2_grp", "pwm3_grp";
++					function = "pwm";
++				};
++
++				pinmux_uart1: uart1 {
++					groups = "uart1_grp";
++					function = "uart1";
++				};
++			};
++		};
++	};
++
+ 	lcpll0: lcpll0@1800c100 {
+ 		#clock-cells = <1>;
+ 		compatible = "brcm,nsp-lcpll0";