Remove the experimental functions psa_generate_key_ext() and
psa_key_derivation_output_key_ext(), which require a flexible array member
and therefore break C++ code that includes Mbed TLS headers. They have been
replaced by psa_generate_key_custom() and
psa_key_derivation_output_key_custom().
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
3077f2f9c6