reset: socfpga: add error handling and release mem-region

In case of an error, call release_mem_region when an error happens
during allocation of resources. Also add error handling for the case
that reset_controller_register fails.

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>