crypto: caam - fix DKP detection logic

The detection for DKP (Derived Key Protocol) relied on the value
of the setkey function.  This was broken by the recent change which
added des3_aead_setkey.

This patch fixes this by introducing a new flag for DKP and setting
that where needed.

Fixes: 1b52c409

 ("crypto: caam - Forbid 2-key 3DES in FIPS mode")
Reported-by: Horia Geantă <horia.geanta@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Tested-by: Horia Geantă <horia.geanta@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>