target/arc: Introduce L1I,L1D,L2 caches support

target/arc: Introduce L1I,L1D,L2 caches support

With this commit we introduce L1 and L2 cache
flush and invalidate operations which are necessary for
getting/setting actual data during memory r/w operations.

We introduce L2 cache support, which is not presented
on currently support EMSK board. But L2 is presented
on HSDK board, which soon will be introduced.

Change-Id: I2fda505a47ecb8833cc9f5ffe24f6a4e22ab6eb0
Signed-off-by: Evgeniy Didin <didin@synopsys.com>
Reviewed-on: http://openocd.zylin.com/5688
Reviewed-by: Oleksij Rempel <linux@rempel-privat.de>
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>