iio: adc: Add check for devm_request_threaded_irq

iio: adc: Add check for devm_request_threaded_irq

BugLink: https://bugs.launchpad.net/bugs/1969110
[ Upstream commit b30537a4cedcacf0ade2f33ebb7610178ed1e7d7 ]

As the potential failure of the devm_request_threaded_irq(),
it should be better to check the return value and return
error if fails.

Fixes: fa659a40b80b ("iio: adc: twl6030-gpadc: Use devm_* API family")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Link: https://lore.kernel.org/r/20220224062849.3280966-1-jiasheng@iscas.ac.cn
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
(cherry picked from commit 82546d91d588e8a9f9821fbc1359b3ad6739f57a)
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>