iio: adc: ad7192: properly check spi_get_device_match_data()

[ Upstream commit b7f99fa1 ]

spi_get_device_match_data() can return a NULL pointer. Hence, let's
check for it.

Signed-off-by: Nuno Sa <nuno.sa@analog.com>
Link: https://patch.msgid.link/20241014-fix-error-check-v1-1-089e1003d12f@analog.com


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>