toolchain: Bump ARC tools to arc-2016.09-rc2

As described at:
4520524b
this commit continues a series of updates of ARC tools.
This time we're updating tools to arc-2016.09-rc2.

This change contains a set of minor fixes and updates.

Signed-off-by: Vlad Zakharov <vzakhar@synopsys.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>