[CRYPTO] padlock: Convert padlock-sha to use crypto_hash

This patch converts padlock-sha to use crypto_hash for its fallback.
It also changes the fallback selection to use selection by type instead
of name.  This is done through the new CRYPTO_ALG_NEED_FALLBACK bit,
which is set if and only if an algorithm needs a fallback of the same
type.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>