Merge pull request ARMmbed#1377 from star297/master

Update Teensy3.1 PinNames.h

Author: 0xc0170

libraries/mbed/targets/hal/TARGET_Freescale/TARGET_K20XX/TARGET_TEENSY3_1/PinNames.h

@@ -262,8 +262,8 @@ typedef enum {
     A19 = PTC11,
     A20 = PTE0,
 
-    I2C_SCL = PTB3,
-    I2C_SDA = PTB2,
+    I2C_SCL = PTB2,
+    I2C_SDA = PTB3,
 
     SPI_SCK = PTC5,  // sclk
     SPI_DOUT = PTC6, // mosi