drm/amd/display: Add null check for top_pipe_to_program in commit_planes_for_stream

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Add null check for top_pipe_to_program in commit_planes_for_stream This commit addresses a null pointer dereference issue in the `commit_planes_for_stream` function at line 4140. The issue could occur when `top_pipe_to_program` is null. The fix adds a check to ensure `top_pipe_to_program` is not null before accessing its stream_res. This prevents a null pointer dereference. Reported by smatch: drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc.c:4140 commit_planes_for_stream() error: we previously assumed 'top_pipe_to_program' could be null (see line 3906)

References

• https://git.kernel.org/stable/c/1ebfa6663807c144be8c8b6727375012409d2356
• https://git.kernel.org/stable/c/8ab59527852a6f7780aad6185729550ca0569122
• https://git.kernel.org/stable/c/40193ff73630adf76bc0d82398f7d90fb576dba4
• https://git.kernel.org/stable/c/e47e563c6f0db7d792a559301862c19ead0dfc2f
• https://git.kernel.org/stable/c/3929e382e4758aff42da0102a60d13337c99d3b8
• https://git.kernel.org/stable/c/73efd2a611b62fee71a7b7f27d9d08bb60da8a72
• https://git.kernel.org/stable/c/66d71a72539e173a9b00ca0b1852cbaa5f5bf1ad