stm32: Replace stray tabs with spaces.

ports/stm32/extint.c

@@ -83,7 +83,7 @@
 
 // TODO Add python method to change callback object.
 
-#define EXTI_OFFSET	(EXTI_BASE - PERIPH_BASE)
+#define EXTI_OFFSET (EXTI_BASE - PERIPH_BASE)
 
 // Macro used to set/clear the bit corresponding to the line in the IMR/EMR
 // register in an atomic fashion by using bitband addressing.

ports/stm32/usb.h

@@ -44,8 +44,8 @@ typedef enum {
 } pyb_usb_storage_medium_t;
 
 typedef enum {
-	USB_PHY_FS_ID = 0,
-	USB_PHY_HS_ID = 1,
+    USB_PHY_FS_ID = 0,
+    USB_PHY_HS_ID = 1,
 } USB_PHY_ID;
 
 extern mp_uint_t pyb_usb_flags;