Add register detection function to accelerator. Provided a tool that
user can checking differential register through Debugfs.
e.g.
    cd /sys/kernel/debug/hisi_zip/<bdf>/zip_dfx
    cat diff_regs
Signed-off-by: Longfang Liu <liulongfang@huawei.com>
Signed-off-by: Kai Ye <yekai13@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>