[CRYPTO] api: Add support for multiple template parameters

This patch adds support for having multiple parameters to
a template, separated by a comma.  It also adds support
for integer parameters in addition to the current algorithm
parameter type.

This will be used by the authenc template which will have
four parameters: the authentication algorithm, the encryption
algorithm, the authentication size and the encryption key
length.

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