arduino header: fix pedantic compiler warnings

sys/arduino/include/arduino.hpp

@@ -34,7 +34,7 @@ extern "C" {
 enum {
     INPUT,              /**< configure pin as input */
     OUTPUT,             /**< configure pin as output */
-    INPUT_PULLUP,       /**< configure pin as input with pull-up resistor */
+    INPUT_PULLUP        /**< configure pin as input with pull-up resistor */
 };
 
 /**
@@ -42,7 +42,7 @@ enum {
  */
 enum {
     LOW = 0,            /**< pin is cleared */
-    HIGH = 1,           /**< pin is set */
+    HIGH = 1            /**< pin is set */
 };
 
 /**

sys/arduino/include/serialport.hpp

@@ -36,7 +36,7 @@ enum SerialFormat {
     BIN,            /**< format to binary representation */
     OCT,            /**< format to octal representation */
     DEC,            /**< format to decimal representation */
-    HEX,            /**< format to hex representation */
+    HEX             /**< format to hex representation */
 };
 
 /**