iio: adis16400: do not return ints in irq handlers

iio: adis16400: do not return ints in irq handlers

[ Upstream commit ab3df79782e7d8a27a58576c9b4e8c6c4879ad79 ]

On an IRQ handler we should not return normal error codes as 'irqreturn_t'
is expected.

Not necessary to apply to stable as the original check cannot fail and
as such the bug cannot actually occur.

Fixes: 5eda3550a3cc1 ("staging:iio:adis16400: Preallocate transfer message")
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Signed-off-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20210422101911.135630-3-nuno.sa@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>