icsf.c: add function to generate key pair

Add the function icsf_generate_key_pair() that calls the ICSF service
CSFPGKP.

Signed-off-by: Marcelo Cerri <mhcerri@linux.vnet.ibm.com>
new_host.c: fix formatting in SC_GenerateKeyPair()

Signed-off-by: Marcelo Cerri <mhcerri@linux.vnet.ibm.com>
token-specific function for key pair generation

Add a new token-specific function t_generate_key_pair.

Signed-off-by: Marcelo Cerri <mhcerri@linux.vnet.ibm.com>
icsf: add token-specific function to generate key pairs

Signed-off-by: Marcelo Cerri <mhcerri@linux.vnet.ibm.com>
icsf: add support for sign/verify/encrypt/decrypt with asymmetric keys

Signed-off-by: Marcelo Cerri <mhcerri@linux.vnet.ibm.com>
icsf: refactor encryption functions to support different implementations

This change is needed to support asymmetric and symmetric
implementations.

Signed-off-by: Marcelo Cerri <mhcerri@linux.vnet.ibm.com>
icsf: add login to decide between symmetric and asymmetric encryption

Signed-off-by: Marcelo Cerri <mhcerri@linux.vnet.ibm.com>
icsf: add support for asymmetric encryption

Signed-off-by: Marcelo Cerri <mhcerri@linux.vnet.ibm.com>