riscv: cacheinfo: Fix node reference leak in populate_cache_leaves

commit bf4a195f06 upstream.

Currently, the while loop drops the reference to prev in each iteration.
If the loop terminates early due to a break, the final of_node_put(np)
correctly drops the reference to the current node.

However, if the loop terminates naturally because np == NULL, calling
of_node_put(np) is a no-op. This leaves the last valid node stored in
prev without its reference dropped, resulting in a node reference leak.

Fix this by changing the final `of_node_put(np)` to `of_node_put(prev)`.

Fixes: 94f9bf118f ("RISC-V: Fix of_node_* refcount")
Cc: stable@vger.kernel.org
Assisted-by: Gemini:gemini-3.1-pro
Signed-off-by: Zishun Yi <vulab@iscas.ac.cn>
Link: https://patch.msgid.link/20260509074040.1747800-1-vulab@iscas.ac.cn
Signed-off-by: Paul Walmsley <pjw@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/riscv/kernel/cacheinfo.c

@@ -128,7 +128,7 @@ int populate_cache_leaves(unsigned int cpu)
 			ci_leaf_init(this_leaf++, CACHE_TYPE_DATA, level);
 		levels = level;
 	}
-	of_node_put(np);
+	of_node_put(prev);
 
 	return 0;
 }