Update the readme file for the hc-sr04_ultrasonic_sensor and pir-sensor samples
Add a note the readme files for hc-sr04_ultrasonic_sensor and pir-sensor samples that the sample will work on RPI4 only.
QNXE-1061
Add a note the readme files for hc-sr04_ultrasonic_sensor and pir-sensor samples that the sample will work on RPI4 only.
QNXE-1061