[Feature] pacakge generic boundary

[taichi-ishitani]

Some IPs use a lot of typedefs defined by its structued config parameters.
For example:

• https://github.com/pezy-computing/pzbcm/blob/985e7147ab42682e62f32604433090b3be5f8482/pzcorebus_common/pzcorebus_if_internal_macros.svh#L10-L29
• https://github.com/pezy-computing/pzbcm/blob/985e7147ab42682e62f32604433090b3be5f8482/pzcorebus_common/pzcorebus_if.sv#L18

For this kind of useage, config parameters and typedefs should be handled together.
I'd like to introduce the package generic boundary to allow to specify a generic package as a generic argument.

Example code:

package foo_pkg::<AW: const, DW: const> {
  const ADDRESS_WIDTH: u32 = AW;
  const DATA_WIDTH:    u32 = DW;

  type address_t = logic<ADDRESS_WIDTH>;
  type data_t    = logic<DATA_WIDTH>;
}


module foo_top::<PKG: foo_pkg> (
  i_address: input PKG::address_t,
  i_data:    input PKG::data_t,
) {
  import PKG::*;

  var address: address_t;
}

inst u_foo: foo_top::<foo_pkg::<16, 32>>(
  i_address: address,
  i_data:    data,
);

[taichi-ishitani]

For the above sample, foo_pkg has only 2 generic parameters but an actual packages may have more generic parameters. I think it is very troublesome to write such generic instance everywhere it is used.

To avoid this, I think it would be nice to create an alias to such generic package instance.