ARC Fix for 4.7-rc6

- Reinstate dwarf unwinder/loadable-modules with new gnu tools

ARC updates for 4.7-rc3

- Revert of ll-sc backoff retry workaround in atomics/spinlocks as hardware
  is now proven to work just fine

- Typo fixes (Thanks Andrea Gelmini)

- Removal of obsolete DT property (Alexey)

- Other minor fixes

This is the 4.6.2 stable release

This is the 4.5.7 stable release

This is the 4.4.13 stable release

This is the 3.14.72 stable release

Linux 4.1.26

Linux 3.18.35

This is the 4.6.1 stable release

This is the 4.5.6 stable release