Compilation fix for newer mbed-os

Fork of X_NUCLEO_IDB0XA1 by ST

Revision:
309:42e0b6ff504d
Parent:
253:9665a6f8bbdb
--- a/x-nucleo-idb0xa1/x_nucleo_idb0xa1_targets.h	Mon Sep 04 14:15:45 2017 +0000
+++ b/x-nucleo-idb0xa1/x_nucleo_idb0xa1_targets.h	Mon Sep 04 14:21:08 2017 +0000
@@ -47,7 +47,10 @@
 #define IDB0XA1_PIN_SPI_MISO   (D12)
 #define IDB0XA1_PIN_SPI_nCS    (A1)
 #define IDB0XA1_PIN_SPI_RESET  (D7)
+
+#ifndef IDB0XA1_PIN_SPI_IRQ
 #define IDB0XA1_PIN_SPI_IRQ    (A0)
+#endif
 
 /* NOTE: Define macro 'IDB0XA1_D13_PATCH' if you want to compile for a specifically
          modified version of the X_NUCLEO_IDB0XA1 expansion board in