vexpress-uboot: only set env if bootargs are specified

If env is specified, U-Boot module will wait for U-Boot prompt and then
interrupt the boot sequence so it should be updated. The vexpress module
that used it always set the env to contain bootargs (even if they were
None), always causing boot to be interrupted, even when that is not
necessary. This update means that boot will be interrupted only if
bootargs were specified (and therefore env needs to be updated).
1 file changed
tree: 9f391ec93b172266d0913bda38906da011da925b
  1. devlib/
  2. doc/
  3. src/
  4. .gitignore
  5. README.rst
  6. setup.py