fix(linux): Fill in missing commands for USB-DFU flash eMMC

For USB-DFU flashing to eMMC section, fill in the missing
commands to flash tispl.bin and u-boot.img.

Signed-off-by: Judith Mendez <[email protected]>

Author: jmenti

source/linux/Foundational_Components/U-Boot/UG-Memory-K3.rst

@@ -362,13 +362,19 @@ Then transfer each desired binary from the host to the device:
    .. code-block:: console
 
       $ sudo dfu-util -R -a tiboot3.bin.raw -D tiboot3.bin
+      $ sudo dfu-util -R -a tispl.bin.raw -D tispl.bin
+      $ sudo dfu-util -R -a u-boot.img.raw -D u-boot.img
 
 - Device:
 
    .. code-block:: console
 
       ##DOWNLOAD ... OK
       Ctrl+C to exit ...
+      ##DOWNLOAD ... OK
+      Ctrl+C to exit ...
+      ##DOWNLOAD ... OK
+      Ctrl+C to exit ...
 
 Flashing an SD card from a host PC
 ==================================