sm8450-common: rootdir: Enable mgame mi_thermald mode

Out of all the modes that run the CPU at advertised speeds without
underclocking, mgame has the most conservative thermal limits.

Change-Id: I491f608a7be5c9497c70b3e49501d7abf58a980c
Signed-off-by: Jens Reidel <adrian@travitia.xyz>

rootdir/etc/init.xiaomi_sm8450.rc

@@ -153,6 +153,9 @@ on post-fs-data
 on property:sys.boot_completed=1
     start qrtr-lookup
 
+    # Set thermal mode to mgame
+    write /sys/devices/virtual/thermal/thermal_message/sconfig 20
+
 on charger
     chown system system /sys/class/backlight/panel0-backlight/brightness
     chown system system /sys/class/backlight/panel1-backlight/brightness