Further dunfell updates

Further dunfell updates

Changes:
- Switch meta-virtualiztion, meta-intel, and meta-freescale* to
  their new dunfell branches.
- Add new upstream meta-arm repository that is now a requirement for
  meta-ti.
- Update commit IDs in default.xml to latest on master/dunfell. The
  3.1 dunfell release is final now; the poky commit used is a few
  past the tagged release commit, the extra changes are all release
  documentation fixes.

Bug-AGL: SPEC-3302

Signed-off-by: Scott Murray <scott.murray@konsulko.com>
Change-Id: I36260fc89b1a166aff1b4a20ca0fce80cb7a9c19