crypto: curve25519 - add kpp selftest

In preparation of introducing KPP implementations of Curve25519, import
the set of test cases proposed by the Zinc patch set, but converted to
the KPP format.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/crypto/testmgr.c b/crypto/testmgr.c
index 5357728..82513b6 100644
--- a/crypto/testmgr.c
+++ b/crypto/testmgr.c
@@ -4318,6 +4318,12 @@ static const struct alg_test_desc alg_test_descs[] = {
 		.test = alg_test_null,
 		.fips_allowed = 1,
 	}, {
+		.alg = "curve25519",
+		.test = alg_test_kpp,
+		.suite = {
+			.kpp = __VECS(curve25519_tv_template)
+		}
+	}, {
 		.alg = "deflate",
 		.test = alg_test_comp,
 		.fips_allowed = 1,