Since openssl commit:

| 3d5a7578e09a Add ChaCha related ciphers to default provider

the chacha20-poly1305 dhgex tests ("make t-exec LTESTS=dhgex") are failing.

The problem is currently tracked in OpenSSL Issue #13064.

To work around this problem, mark OpenSSL-3.0 alpha to have a broken chacha20
implementation. OpenSSL will use the working internal chacha20 implementation.

Link: openssl/openssl#13064
Link: openssl/openssl@3d5a757
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>