iio: proximity: vcnl3020: Drop unnecessary alignment requirement for i2c device

I2C does not by default use buffers directly for DMA so there is
no need to ensure they are DMA safe.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Ivan Mikhaylov <i.mikhaylov@yadro.com>
Acked-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20220508175712.647246-88-jic23@kernel.org