STM: add qspi pin names for DISCO_L475VG_IOT01A

Author: maciejbocianski

targets/TARGET_STM/TARGET_STM32L4/TARGET_STM32L475xG/TARGET_DISCO_L475VG_IOT01A/PinNames.h

@@ -240,6 +240,14 @@ typedef enum {
     SPI_SCK     = D13,
     SPI_CS      = D10,
     PWM_OUT     = D9,
+#ifdef DEVICE_QSPI
+    QSPI_PIN_IO0 = PE_12,
+    QSPI_PIN_IO1 = PE_13,
+    QSPI_PIN_IO2 = PE_14,
+    QSPI_PIN_IO3 = PE_15,
+    QSPI_PIN_SCK = PE_10,
+    QSPI_PIN_CSN = PE_11,
+#endif
 
     /**** USB pins ****/
     USB_OTG_FS_DM = PA_11,