4th set of IIO fixes for the 4.12 cycle.
core
- fix IIO_VAL_FRACTIONAL_LOG2 handling for negative values.
bmg160
- reset chip on probe to avoid a failure on some systems
cros_ec
- return type correctly when reading raw and calibbias data.
hid-sensor-accel
- fix a duplicate scan index error due to wrong number of channels
for gravity sensor.
hid-sensors
- ensure a get_feature is always done before the first set feature to
avoid issues with wrong cached values.
st-pressure
- initalize lps22hb boot time to avoid giving stale data.