Introduce ARCv2 tcl config files

Introduce ARCv2 tcl config files

With this commit we add tcl files which describes
ARCv2 architecture features and configure files
for ARCv2 EMSK board.

Changes since v1:
-Moved from http://openocd.zylin.com/#/c/5332/4
 into separate commit.

Changes:
22.01.2020:
-Removed "actionpoints" handling code in
 tcl/cpu/arc/v2.tcl because this capability
 is not supported yet.

Changes:
17.03.2020:
-Update Licence headers
-Cleanup indents
-Removed "reset halt" in boards .tcl
-Updated adapter frequency commands

Changes:
15.03.2020:
-Removed "init" in the of boards .tcl

Change-Id: I51bf620abe7b8e046e1dccc861a7d963965d3a42
Signed-off-by: Evgeniy Didin <didin@synopsys.com>
Cc: Alexey Brodkin <abrodkin@synopsys.com>
Reviewed-on: http://openocd.zylin.com/5350
Tested-by: jenkins
Reviewed-by: Oleksij Rempel <linux@rempel-privat.de>