Fix parent-device reference leak due to SPI-core taking an unnecessary
reference to the parent when allocating the master structure, a
reference that was never released.
Note that driver core takes its own reference to the parent when the
master device is registered.
Fixes: 49dce689ad4e ("spi doesn't need class_device") Signed-off-by: Johan Hovold <johan@kernel.org> Signed-off-by: Mark Brown <broonie@kernel.org> Cc: stable@vger.kernel.org