obs-qsv11: Remove non-functional CQM-related code

[DeeDeeG]

Description

Remove a function that, due to other, previous code removals, doesn't do anything anymore.

This profile_modified callback function exists simply to toggle visibility of a "CQM" encoder option in the settings UI; however, said option has been removed from the plugin years ago. There is no option to toggle anymore, so this code effectively does nothing now. This PR removes the non-functioning function.

Motivation and Context

Cleaning up a "fancy no-op with extra steps" function I saw when stepping through this plugin in the Visual Studio debugger.

(It used to do something, but the stuff it did has been removed from the codebase some time ago.)

History of this code: This callback function and the "CQM" setting it used to toggle were added in #2077. Then the standalone "CQM" setting was phased out and rolled into a combined "Subjective Video Enhancements" setting in #3035. That PR migrated existing users' settings from "CQM" to "Subjective Video Enhancements." (At that point this callback could have been removed, as it didn't do anything anymore.) And lastly, all "Subjective Video Enhancements" and "CQM"-related code but this callback function were removed by #10388.

So, in summary, there is nothing left of CQM in obs-qsv11 besides this one last check/toggle that doesn't accomplish anything anymore.

How Has This Been Tested?

obs-qsv11 encoder plugin still works with the dead code removed (identically as it did before). Tested on self-compiled OBS with this change, on Windows 10, with a UHD770 iGPU (12700K).

Recordings succeeded and played back fine. Switching the encoder profile from High to Baseline etc. and back works fine. Everything looks normal when stepping through with the debugger.

Types of changes

• Code cleanup (non-breaking change which makes code smaller or more readable)

Checklist:

• My code has been run through clang-format.
• I have read the contributing document.
• My code is not on the master branch.
• The code has been tested.
• All commit messages are properly formatted and commits squashed where appropriate.
• I have included updates to all appropriate documentation.