include: Add distance channel sensor
include: Add distance channel sensor

Add a distance channel in the sensor interface to be used with
time Of flight sensors (vl53l0X for example).This will indicate
the distance from the sensor to the target, in millimeters.

Signed-off-by: Vincent Veron <d0437362c556ce51fce5edebef610c1693e26118@st.com>

finikorg/zephyr,mbolivar/zephyr,galak/zephyr,zephyriot/zephyr,ldts/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,punitvara/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,mbolivar/zephyr,ldts/zephyr,finikorg/zephyr,zephyriot/zephyr,GiulianoFranchetto/zephyr,kraj/zephyr,zephyriot/zephyr,zephyriot/zephyr,ldts/zephyr,explora26/zephyr,nashif/zephyr,zephyriot/zephyr,ldts/zephyr,galak/zephyr,nashif/zephyr,mbolivar/zephyr,explora26/zephyr,Vudentz/zephyr,GiulianoFranchetto/zephyr,GiulianoFranchetto/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,mbolivar/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,mbolivar/zephyr,galak/zephyr,galak/zephyr,nashif/zephyr,Vudentz/zephyr,punitvara/zephyr,kraj/zephyr,nashif/zephyr,Vudentz/zephyr,punitvara/zephyr,explora26/zephyr,Vudentz/zephyr,ldts/zephyr,kraj/zephyr,explora26/zephyr,punitvara/zephyr,explora26/zephyr,kraj/zephyr,nashif/zephyr,GiulianoFranchetto/zephyr,finikorg/zephyr,GiulianoFranchetto/zephyr,Vudentz/zephyr,punitvara/zephyr,kraj/zephyr