Remove useless -D_ENDIAN from MPE/iX-gcc config
Remove useless -D_ENDIAN from MPE/iX-gcc config

Reviewed-by: Andy Polyakov <015edf36635e030d5e009e08808a59984e629740@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/5564)

openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl