Added odroid xu4 specific system files

hardware_specific/odroid-xu4/README

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+Included are the the following files to more gracefully handle temperatures on the odroid xu4 running with systemd.
+
+update-fans.sh is the script that actually updates the system files for the fan. Namely the fan speed and temperature settings.
+It gets installed into /usr/local/bin/
+
+update-fans.service is the service that calls the script to update the fans
+update-fans.timer is the systemd timer that updates the fan speeds 5 seconds after systemd starts.
+
+These should be placed in /usr/lib/systemd/system or wherever your systemd services and timers are stored
+
+Finally the timer should be activated with "systemctl enable update-fans.timer".
+If you don't feel like restarting to change the fan settings immediately, you can run "systemctl start update-fans.service"
+

hardware_specific/odroid-xu4/update-fans.service

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+[Unit]
+Description=update-fans
+
+[Service]
+Type=simple
+ExecStart=/usr/local/bin/update-fans.sh

hardware_specific/odroid-xu4/update-fans.sh

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+#!/usr/bin/env bash
+
+#
+# Run as root as a systemd service at startup
+#
+
+# Set the triggering temp levels to 40/75/85
+# Supposedly continuous operation at over 85C is not recommended
+echo "40 75 85" > /sys/devices/odroid_fan.13/temp_levels
+# Set the fan speeds to:
+# 1 at below 40C (Off)
+# 28% above 40C and below 75C
+# 75% above 75C and below 85C
+# 100% above 85C
+echo "1 28 75 100" > /sys/devices/odroid_fan.13/fan_speeds
+
+# Display the current fan speed and temperature
+#
+# Sensor 2 seems to be the processor, or atleast the one that triggers the fan speeds
+#
+# Sensor 4 is always lower than the other sensors and doesn't change as fast under CPU load. Possibly memory controller?
+#cat /sys/devices/odroid_fan.13/pwm_duty && sudo cat /sys/devices/10060000.tmu/temp

hardware_specific/odroid-xu4/update-fans.timer

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+[Unit]
+Description=Update the system fan and temperature setting at startup
+
+[Timer]
+OnStartupSec=5
+
+[Install]
+WantedBy=multi-user.target