[NUCLEO_F401RE] Remove PB_11 pin.

Author: bcostm

libraries/mbed/targets/hal/TARGET_STM/TARGET_NUCLEO_F401RE/PinNames.h

@@ -93,7 +93,6 @@ typedef enum {
   PB_8  = 0x18,
   PB_9  = 0x19,
   PB_10 = 0x1A,
-  PB_11 = 0x1B,
   PB_12 = 0x1C,
   PB_13 = 0x1D,
   PB_14 = 0x1E,