iio: dac: ti-dac7311: Add check for spi_setup

Add check for the return value of spi_setup() and return the error
if it fails in order to catch the error.

Signed-off-by: Chen Ni <nichen@iscas.ac.cn>
Link: https://patch.msgid.link/20240705084250.3006527-1-nichen@iscas.ac.cn


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>