UBUNTU-CVE-2026-90219: Medium severity ubuntu/linux-azure vulnerability

In the Linux kernel, the following vulnerability has been resolved: RDMA/cxgb4: Free debugfs on registration failure c4iwalloc() creates the per-device debugfs tree (dev->debugfsroot via setupdebugfs()), but it is removed only in c4iwremove(), not in c4iwdealloc(). When RDMA device registration fails, the registration worker's errdeallocctx path calls c4iwdealloc() directly, bypassing c4iwremove(), so the debugfs dentries leak and outlive the freed c4iwdev. Move debugfsremoverecursive() into c4iwdealloc() so every path that frees ctx->dev also removes its debugfs tree.