cache: starfive: fix device node leak in starlink_cache_init()

cache: starfive: fix device node leak in starlink_cache_init()

of_find_matching_node() returns a device_node with refcount incremented.

Use __free(device_node) attribute to automatically call of_node_put()
when the variable goes out of scope, preventing the refcount leak.

Fixes: cabff60ca77d ("cache: Add StarFive StarLink cache management")
Signed-off-by: Felix Gu <ustc.gu@gmail.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>