libffi: back-port support for ARC

Support for ARC CPUs was added in libffi after 3.0.13 vesion was cut and up
until now no new release has been done. So to enale libffi on ARC we need this
set of patches.

These are corrsponding commits in libffi:
 * b082e15091961373c03d10ed0251f619ebb6ed76 - Add ARC support
 * 0f8690a84c874ec09a090c8c6adfb93c594acac6 - Rebuild for ARC additions
 * d918d47809c174d62283306b282749f8db93661f - arc: Fix build error

The first patch was modified a bit (cut changelog part) to accomodate
changes not related to ARC between 3.0.14 and changes in question.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Misca Jonker <mjonker@synopsys.com>

Cc: Peter Korsgaard <peter@korsgaard.com>
Cc: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>