* config/tc-s390.c (md_parse_option): Add cpu type z990.

    * config/tc-s390.c (md_parse_option): Add cpu type z990.
        (md_begin): Add minimal cpu type logic for instructions with different
        binary format depending on the cpu.
        (md_assemble): Remove check for minimal cpu.
        (s390_insert_operand): Add support for long displacements.
        (md_gather_operands): Likewise.
        (tc_s390_fix_adjustable): Likewise.
        (tc_s390_force_relocation): Likewise.
        (md_apply_fix3): Likewise.