iio: pressure: bmp280: Use sleep and forced mode for oneshot captures

iio: pressure: bmp280: Use sleep and forced mode for oneshot captures

Add forced mode support in sensors BMP28x, BME28x, BMP3xx and BMP58x.
Sensors BMP18x and BMP085 are old and do not support this feature so
their operation is not affected at all.

Essentially, up to now, the rest of the sensors were used in normal mode
all the time. This means that they are continuously doing measurements
even though these measurements are not used. Even though the sensor does
provide PM support, to cover all the possible use cases, the sensor needs
to go into sleep mode and wake up whenever necessary.

The idea is that the sensor is by default in sleep mode, wakes up in
forced mode when a oneshot capture is requested, or in normal mode
when the buffer is enabled. The difference lays in the fact that in
forced mode, the sensor does only one conversion and goes back to sleep
while in normal mode, the sensor does continuous measurements with the
frequency that was set in the ODR registers.

The bmpX_chip_config() functions which are responsible for applying
the requested configuration to the sensor, are modified accordingly
in order to set the sensor by default in sleep mode.

DEEP STANDBY, Low Power NORMAL and CONTINUOUS modes, supported only by
the BMP58x version, are not added.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Vasileios Amoiridis <vassilisamir@gmail.com>
Link: https://patch.msgid.link/20241017233022.238250-2-vassilisamir@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>