Commit 7b2cd92a ("crypto: api - Fix
zeroing on free") added modular user of ksize(). Export that to fix
crypto.ko compilation.

Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NKirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi>