jimtcl: switch to github

jimtcl: switch to github

The 'historically' main repository of jimtcl in repo.or.cz has
lost sync with the github current main repository since July 2020.
The new tag 0.80 is not present in repo.or.cz.
The developer of jimtcl has been in contact with the admins of
repo.or.cz to fix the not better described sync issues and has now
decided to stop any further tentative. A new README has been added
on 2020-11-19 in the old repository to inform that it is abandoned
in favour of github. The old content in repo.or.cz will remain due
to forks that still exists in the same server.

Switch OpenOCD git submodules to fetch jimtcl code from the main
development repository in github.

Change-Id: Ia2d59f1347ccfe374538b38131badfd46054eb91
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: http://openocd.zylin.com/5948
Tested-by: jenkins
Reviewed-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>