use updated device tree, avoid oom

workaround `fatal error: th1520-lichee-cluster-4a-16g.dts: No such file or directory`

Author: pbraun9

bare-metal/elastic-metal/reference-content/elastic-metal-rv1-guidelines.mdx

@@ -72,35 +72,43 @@ Linux kernel.
     cd linux/
     make revyos_defconfig
     # This can take several hours.
-    make -j
+    make -j4
     sudo make modules_install
     cd ..
     ```
 5. Build OpenSBI.
    ```bash
    cd opensbi/
-   make PLATFORM=generic -j
+   make PLATFORM=generic -j4
    cd ..
    ```
 6. Build and install the FIT image.
    ```bash
    cd em-rv1/fit/
 
+   # Fix path to board device tree
+   ls -lF ../../linux/arch/riscv/boot/dts/thead/th1520-lichee-pi-4a-16g.dts
+   vi em-rv1-c4m16s128-a.dts
+
+   #include "th1520-lichee-pi-4a-16g.dts"
+
    # Build the device tree
    cpp \
     -nostdinc \
-    -I ../linux/arch/riscv/boot/dts/thead/ \
-    -I ../linux/include/ \
+    -I ../../linux/arch/riscv/boot/dts/thead/ \
+    -I ../../linux/include/ \
     -undef \
     -x assembler-with-cpp \
     em-rv1-c4m16s128-a.dts \
     | dtc -o em-rv1-c4m16s128-a.dtb
 
-   # Build the FIT image
+   # Build the FIT image and check
    sudo mv /boot/boot.itb /boot/boot.itb.bak
    sudo mkimage -f em-rv1-c4m16s128-a-boot.its /boot/boot.itb
+   sha256sum ../../linux/arch/riscv/boot/Image
+   sudo mkimage -l /boot/boot.itb
 
-   cd -
+   cd ../..
    ```
 7. Reboot the server to load the new kernel.