When it is failed in shadow_mm, the pin_count should rollback
to the original states before return.

v2:
- split the mixed several error paths for better review. (Zhenyu)

v3:
  increase the pincount after shadow success. (Zhenyu)
Signed-off-by: Nfred gao <fred.gao@intel.com>
Signed-off-by: NZhenyu Wang <zhenyuw@linux.intel.com>