qualcommax: ipq807x: set thermal governor to Bang Bang for Zyxel NBG7815

Add boot script to set a better thermal governor for Zyxel NBG7815 that
makes use of a Fan to cool down the device.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>

target/linux/qualcommax/ipq807x/base-files/etc/init.d/thermal_fan_policy

@@ -0,0 +1,16 @@
+#!/bin/sh /etc/rc.common
+
+START=99
+
+boot() {
+	case $(board_name) in
+	zyxel_nbg7815)
+		# get correct thermal zone defined in DTS
+		aqr_thermal=$(grep -Ril "aqr-thermal" /sys/class/thermal/thermal_zone*/type | cut -d'/' -f 5)
+		tmp103_thermal=$(grep -Ril "tmp103-thermal" /sys/class/thermal/thermal_zone*/type | cut -d'/' -f 5)
+		# setting thermal governor from step_wise to bang_bang
+		echo "bang_bang" > /sys/class/thermal/${aqr_thermal}/policy
+		echo "bang_bang" > /sys/class/thermal/${tmp103_thermal}/policy
+		;;
+	esac
+}

target/linux/qualcommax/ipq807x/config-default

@@ -28,3 +28,4 @@ CONFIG_SPMI=y
 # CONFIG_SPMI_HISI3670 is not set
 CONFIG_SPMI_MSM_PMIC_ARB=y
 # CONFIG_SPMI_PMIC_CLKDIV is not set
+CONFIG_THERMAL_GOV_BANG_BANG=y