EDAC/versalnet: Fix device_node leak in mc_probe()

EDAC/versalnet: Fix device_node leak in mc_probe()

of_parse_phandle() returns a device_node reference that must be released with
of_node_put(). The original code never freed r5_core_node on any exit path,
causing a memory leak.

Fix this by using the automatic cleanup attribute __free(device_node) which
ensures of_node_put() is called when the variable goes out of scope.

Fixes: d5fe2fec6c40 ("EDAC: Add a driver for the AMD Versal NET DDR controller")
Signed-off-by: Felix Gu <ustc.gu@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Shubhrajyoti Datta <shubhrajyoti.datta@amd.com>
Cc: <stable@kernel.org>
Link: https://patch.msgid.link/20260323-versalnet-v1-1-4ab3012635ef@gmail.com