panfrost: Don't leak NIR compute shaders

panfrost: Don't leak NIR compute shaders

We never steal the NIR program or free it explicitly, and the state
tracker expects drivers to take ownership of the program object. Since
panfrost doesn't need to keep the original NIR shader around for
compute, let's just free it before returning.

Fixes: 40372bd720fe ("panfrost: Implement a disk cache")
Cc: stable
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26424>
(cherry picked from commit 692a4b18047a9549ec993c6bded598c5f0c06de0)