[ion] Set all GPIOs to analog/non-pulled in release mode

Change-Id: Ie7dedc1089b0023a124af04a4d016cc9a843e28b

ion/src/device/device.cpp

@@ -59,10 +59,15 @@ void initFPU() {
 
 void init() {
   initClocks();
+#ifndef DEBUG
+  /* In debug mode, we want to keep the SWD port configured as such.
+   * In release mode, we're setting all the inputs to analog, non-pulled state
+   * to save power. */
   for (int g=0; g<5; g++) {
     GPIO(g).MODER()->set(0xFFFFFFFF); // All to "Analog"
     GPIO(g).PUPDR()->set(0x00000000); // All to "None"
   }
+#endif
   initPeripherals();
 }