arch: arc: Restore MPU registers to its initial states between tests

EMSK boards can't be reset between tests due to hardware configures.
MPU v3 configs in previous test could cause exceptions in the following
tests. This commit fixes this issue by restoring MPU registers initial
states at early init stage.

Signed-off-by: Yuguo Zou <yuguo.zou@synopsys.com>
3 files changed