drivers/sensor/: lis2dux12: fix ODR setting

In lis2dux12_freq_to_odr_val, the loop through the array of possible ODR
frequencies can break sooner than expected if power-mode is
set to High Performance mode and the requested ODR is less than or
equal to 25Hz.

Moreover, move the "odr |= 0x10" statement used for HP mode in the
chip_api set_odr_raw() API, so that we enter the HP mode even when the
ODR is set from DT only.

Signed-off-by: Armando Visconti <armando.visconti@st.com>