[M487] Fix SW2/SW3 interchange error in NUMAKER_IOT_M487

Author: ccli8

targets/TARGET_NUVOTON/TARGET_M480/PinNames.h

@@ -131,10 +131,12 @@ typedef enum {
     // Button naming
 #if TARGET_NUMAKER_PFM_M487
     SW2 = PG_15,
+    SW3 = PF_11,
 #elif TARGET_NUMAKER_IOT_M487
-    SW2 = PG_5,
+    SW2 = PF_11,
+    SW3 = PG_5,
 #endif
-    SW3 = PF_11,
+    
 
 } PinName;