The shim module smuggles GPL-only kernel symbols into the non-GPL binary blob. Because the actual module using those symbols is not GPL compatible this violates the GPL license.

From Linus Torvalds mouth:

anybody who were to change a xyz_GPL to the non-GPL one in order to use it with a non-GPL module would almost immediately fall under the "willful infringement" thing, and that it would make it MUCH easier to get triple damages and/or injunctions, since they clearly knew about it.

In short, nvidia is playing with "please sue me" button.