iio: ti_am335x_adc: optimize memory usage

12 bit ADC data is stored in 32 bits of storage.
Change from u32 to u16 to reduce wasted memory.

Signed-off-by: Zubair Lutfullah <zubair.lutfullah@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
1 file changed