dt-bindings: sensor: lps2xdf: make macros sensor agnostic

The possible settings for the lps22df and lps28dfw sensor are overlapping,
except the Full-Scale mode setting. Threrefore we can change the macros
from LPS22DF_DT_[..] to LPS2xDF_DT_[..].

Signed-off-by: Jonas Remmert <j.remmert@phytec.de>