iio: pressure: HID: hid-sensor-press: Refactor channel initialization

iio: pressure: HID: hid-sensor-press: Refactor channel initialization

Replace the local press_adjust_channel_bit_mask() function with a
compound literal for scan_type initialization to improve code
readability.

Signed-off-by: Natália Salvino André <natalia.andre@ime.usp.br>
Co-developed-by: Pietro Di Consolo Gregorio <pietro.gregorio@usp.br>
Signed-off-by: Pietro Di Consolo Gregorio <pietro.gregorio@usp.br>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>