crypto: marvell/octeontx - use sysfs_emit() to instead of scnprintf()

Replace the open-code with sysfs_emit() to simplify the code.

Signed-off-by: ye xingchen <ye.xingchen@zte.com.cn>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>