x86: simplify .dispNN setting

x86: simplify .dispNN setting

First of all eliminate the disp{16,32,32s} static variables, which are
used solely for setting a temporary variable in build_modrm_byte(). The
effect there can be had without use of such a temporary and without
operand_type_or(), by just setting the single bit each that needs
setting.

Then use operand_type_and_not(..., anydisp) when all dispNN bits want
clearing together.