crypto: caam - add support for RSA key form 2

CAAM RSA private key may have either of three representations.

1. The first representation consists of the pair (n, d), where the
   components have the following meanings:
      n      the RSA modulus
      d      the RSA private exponent

2. The second representation consists of the triplet (p, q, d), where
the
   components have the following meanings:
      p      the first prime factor of the RSA modulus n
      q      the second prime factor of the RSA modulus n
      d      the RSA private exponent

3. The third representation consists of the quintuple (p, q, dP, dQ,
qInv),
   where the components have the following meanings:
      p      the first prime factor of the RSA modulus n
      q      the second prime factor of the RSA modulus n
      dP     the first factors's CRT exponent
      dQ     the second factors's CRT exponent
      qInv   the (first) CRT coefficient

The benefit of using the third or the second key form is lower
computational cost for the decryption and signature operations.

This patch adds support for the second RSA private key
representation.

Signed-off-by: Tudor Ambarus <tudor-dan.ambarus@nxp.com>
Signed-off-by: Radu Alexe <radu.alexe@nxp.com>
Signed-off-by: Horia Geantă <horia.geanta@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>