dt-bindings: iio: pressure: Add bindings for MS5637, MS5805, MS5837 and MS8607 sensors

Add device tree bindings for Measurement-Specialties MS5637, MS5805, MS5837 and MS8607 pressure & temperature sensor
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Documentation/devicetree/bindings/iio/pressure/ms5637.txt

+* MS5637 - Measurement-Specialties MS5637, MS5805, MS5837 and MS8607 pressure & temperature sensor
+
+Required properties:
+
+	-compatible: should be one of the following
+		meas,ms5637
+		meas,ms5805
+		meas,ms5837
+		meas,ms8607-temppressure
+	-reg: I2C address of the sensor
+
+Example:
+
+ms5637@76 {
+	compatible = "meas,ms5637";
+	reg = <0x76>;
+};