Add Upscayl's 4x_NMKD-Siax_200k Model

[hollowaykeanho]

Description

Please provide a short description of what feature you're looking forward to
add into the existing repository below. Please include the story behind your
idea as well to give a better visualization of your idea.

Upscayl's upstream uploaded a new 4x_NMKD-Siax_200k model. Let's upstream it.

Expected Behavior

Please specify the expected behavior of your requested feature. Some great and
helpful pointers are your expected interface (e.g. command patterns, simple
sketches of the user interface, etc).

Upscayl's 4x_NMKD-Siax_200k model is available.

Current Absent Behavior

Please specify the current behavior (e.g. workaround, blockage, etc).

Upscayl's 4x_NMKD-Siax_200k model is unavailable.

Attachment

Please drag and drop the necessary data files (e.g. screenshot, logs, etc)
below.

[hollowaykeanho]

committed in f54d959