Update UEFI Frimware

When Jetpack version is changed or modify kernel, you also need to update UEFI firmware.
If UEFI firmware and system image is not matched, device can't boot up.

BE CAREFUL!!

When you upgrade UEFI firmware to Jetpack 6(R36.4.ga), you CAN NOT downgrade to Jetpack 5(R35.3.ga) for now.

Update from demo image

1. Download demo image for your product, and unzip file.
2. Device enter to recovery mode
3. unzip <Product>_hostflash.tbz2 and flash

   $ tar -xvf <hostflash.tbz2 file>
   $ sudo hostflash/host_flash_qspi.sh

The device will automatically reboot after flash completed, which takes about 6 minutes.