Make DH_check set some error bits in recently added error

Make DH_check set some error bits in recently added error

The pre-existing error cases where DH_check returned zero
are not related to the dh params in any way, but are only
triggered by out-of-memory errors, therefore having *ret
set to zero feels right, but since the new error case is
triggered by too large p values that is something different.
On the other hand some callers of this function might not
be prepared to handle the return value correctly but only
rely on *ret. Therefore we set some error bits in *ret as
additional safety measure.

Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/21533)