RT Kernel Compilation Error For Lamobo R1

The current kernel version of the board is 4.9.7, and I am trying to update it to 5.9 with the Real Time Kernel patch.

For compilation I first got the default sunxi config as follows:

make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- sunxi_defconfig

After that I enabled Expert Mode to be able to select the Preempt RT option in General Options of the make menuconfig.

After that I started compiling, and after a while I got the following error:

DTC     arch/arm/boot/dts/sun4i-a10-a1000.dtb
    In file included from arch/arm/boot/dts/sun4i-a10-a1000.dts:46:0:
    arch/arm/boot/dts/sun4i-a10.dtsi:44:41: fatal error: dt-bindings/thermal/thermal.h: No such file or directory
    #include <dt-bindings/thermal/thermal.h>

It would be really helpful If someone could point me on what the reason could be for this include file error or tell me how to correctly install RT for this board. As I am not familiar with this board I do not know if the latest kernel version should work with this board and the RT Patch.