iio: pressure: bmp280: Use char instead of s32 for data buffer

iio: pressure: bmp280: Use char instead of s32 for data buffer

As it was reported and discussed here [1], storing the sensor data in an
endian aware s32 buffer is not optimal. Advertising the timestamp as an
addition of 2 s32 variables which is also implied is again not the best
practice. For that reason, change the s32 sensor_data buffer to a u8
buffer and align it properly.

[1]: https://lore.kernel.org/linux-iio/73d13cc0-afb9-4306-b498-5d821728c3ba@stanley.mountain/

Signed-off-by: Vasileios Amoiridis <vassilisamir@gmail.com>
Link: https://patch.msgid.link/20240930202353.38203-3-vassilisamir@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>