mbedtls_pk_parse_key() makes a temporary copy of the key when it calls
pk_parse_key_pkcs8_encrypted_der(), because that function requires a
writable buffer. pk_parse_key_pkcs8_encrypted_der() always rejects an
empty password, so skip calling it in that case, which allows us to
skip the allocation as well.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
