Implement specialized function to clenup caches (and therefore
sync instruction and data caches) which can be used for cleanup before linux
launch or to sync caches during U-Boot self-relocation.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>