crypto: sha - Fix build error due to crypto_sha1_update

On Tue, Aug 16, 2011 at 03:22:34PM +1000, Stephen Rothwell wrote:
>
> After merging the final tree, today's linux-next build (powerpc
> allyesconfig) produced this warning:
>
> In file included from security/integrity/ima/../integrity.h:16:0,
>                  from security/integrity/ima/ima.h:27,
>                  from security/integrity/ima/ima_policy.c:20:
> include/crypto/sha.h:86:10: warning: 'struct shash_desc' declared inside parameter list
> include/crypto/sha.h:86:10: warning: its scope is only this definition or declaration, which is probably not what you want
>
> Introduced by commit 7c390170 ("crypto: sha1 - export sha1_update for
> reuse").  I guess you need to include crypto/hash.h in crypto/sha.h.

This patch fixes this by providing a declaration for struct shash_desc.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>