drm/nouveau/clk/gm20b: Fix memory leak in gm20b_clk_new()

[Markus Elfring]

> It's possible that we expect an usable clk pointer, though I could not find
> the exact usage yet.

I am curious if another developer would like to add helpful background information.


> For security, I will release this pointer only on error paths in this function.

Do you tend to release objects (which are referenced by pointers)?

Regards,
Markus