Provide a query function for the software public key implementation.  This
permits information about such a key to be obtained using
query_asymmetric_key() or KEYCTL_PKEY_QUERY.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Tested-by: NMarcel Holtmann <marcel@holtmann.org>
Reviewed-by: NMarcel Holtmann <marcel@holtmann.org>
Reviewed-by: NDenis Kenzior <denkenz@gmail.com>
Tested-by: NDenis Kenzior <denkenz@gmail.com>
Signed-off-by: NJames Morris <james.morris@microsoft.com>