Add support for parsing the parameters of a NIST P256 or NIST P192 key. Enable signature verification using these keys. The new module is enabled with CONFIG_ECDSA: Elliptic Curve Digital Signature Algorithm (NIST P192, P256 etc.) is A NIST cryptographic standard algorithm. Only signature verification is implemented. Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: "David S. Miller" <davem@davemloft.net> Cc: linux-crypto@vger.kernel.org Signed-off-by: Stefan Berger <stefanb@linux.ibm.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>