iio: adc: vf610_adc: use devm_* and dev_err_probe() to simple code

Use devm_* and dev_err_probe() simplify probe function and remove
vf610_adc_remove().

Reviewed-by: Haibo Chen <haibo.chen@nxp.com>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20241126195256.2441622-1-Frank.Li@nxp.com


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