media: ir-spi: Utilise temporary variable for struct device

We have a temporary variable to keep pointer to struct device.
Utilise it inside the ->probe() implementation.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>