crypto: zip - Add Compression/Decompression statistics

Add statistics for compression/decompression hardware offload
under debugfs.

Signed-off-by: Mahipal Challa <Mahipal.Challa@cavium.com>
Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>