Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

The white rabbit repository doesn't include upstream archives for
this version of buildroot, and I don't want to commit them there.
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

After re-testing the whole build procedure, I found some issues:
  - buildroot needs to be patched (one of the makefile is bugged)
  - wget --recursive is not working for compressed files (new ohwr cfg)
  - accordingly, save tars at the end, in case user rebuilds later

wrsw_hal: imported external clock source function from the old repo and removed all compilation warnings

libswitchhw: added more comments, removed old functions which were commented out or not used (nor planned to use)