rpi-config: Take into consideration ENABLE_UART value of 0

Also, validate if the value of it is not 0 or 1.

Fixes: https://github.com/agherzan/meta-raspberrypi/issues/567

Signed-off-by: Andrei Gherzan <andrei@gherzan.com>

recipes-bsp/bootfiles/rpi-config_git.bb

@@ -174,9 +174,11 @@ do_deploy() {
     fi
 
     # UART support
-    if [ "${ENABLE_UART}" = "1" ]; then
+    if [ "${ENABLE_UART}" = "1" ] || [ "${ENABLE_UART}" = "0" ] ; then
         echo "# Enable UART" >>$CONFIG
-        echo "enable_uart=1" >>$CONFIG
+        echo "enable_uart=${ENABLE_UART}" >>$CONFIG
+    else
+        bbfatal "Invalid value for ENABLE_UART [${ENABLE_UART}]. The value for ENABLE_UART can be 0 or 1."
     fi
 
     # Infrared support