crypto: nx - Improve debugfs_create_u{32,64}() handling for atomics

Variables of type atomic{,64}_t can be used fine with
debugfs_create_u{32,64}, when passing a pointer to the embedded counter.
This allows to get rid of the casts, which prevented compiler checks.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>