fbdev: of: display_timing: fix refcount leak in of_get_display_timings()

In the Linux kernel, the following vulnerability has been resolved: fbdev: of: display_timing: fix refcount leak in of_get_display_timings() of_parse_phandle() returns a device_node with refcount incremented, which is stored in 'entry' and then copied to 'native_mode'. When the error paths at lines 184 or 192 jump to 'entryfail', native_mode's refcount is not decremented, causing a refcount leak. Fix this by changing the goto target from 'entryfail' to 'timingfail', which properly calls of_node_put(native_mode) before cleanup.