dts: bindings: stm32-temp*: regroup 'ntc' in common file

Reduce duplication in STM32 dietemp bindings by regrouping the 'ntc'
property declared in both "st,stm32-temp" and "st,stm32c0-temp-cal"
to the shared "st,stm32-temp-common" binding.

"st,stm32-temp-cal" is also modified to block 'ntc' property on include as
no dual-calibration sensors to date require it (this could be changed later
when need arises).

Signed-off-by: Mathieu Choplain <mathieu.choplain@st.com>