can: softing_cs: softingcs_probe(): fix memleak on registration failure

can: softing_cs: softingcs_probe(): fix memleak on registration failure

In case device registration fails during probe, the driver state and
the embedded platform device structure needs to be freed using
platform_device_put() to properly free all resources (e.g. the device
name).

Fixes: 0a0b7a5f7a04 ("can: add driver for Softing card")
Link: https://lore.kernel.org/all/20211222104843.6105-1-johan@kernel.org
Cc: stable@vger.kernel.org # 2.6.38
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>