Staging: iio: adt7316: Change the name from irq_flags to irq_type

Most of the drivers in IIO uses irq_type as the name for
storing the interrupt type and hence change the name from
irq_flags to irq_type for maintaining the consistency.

Signed-off-by: Shreeya Patel <shreeya.patel23498@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>