[ND015D] Incorrect sampled values

The ND015D driver incorrectly interprets the sampled values as PSI, instead of inH20.
Additionally, an unnecessary cast from uint16 to int16 is performed, which saturates values higher than 32768 to that value, resulting in loss of range and the sensor driver reporting a saturated value.

Fix

The pressure formula needs to be corrected to convert inH20 to Pascal, and remove the static cast.