STM32F4: Fix typos, s/F2/F4/.

include/libopencm3/stm32/f4/gpio.h

@@ -255,7 +255,7 @@
 /* --- Function prototypes ------------------------------------------------- */
 
 /*
- * Note: The F2 series has a completely new GPIO peripheral with different
+ * Note: The F4 series has a completely new GPIO peripheral with different
  * configuration options. Here we implement a different API partly to more
  * closely match the peripheral capabilities and also to deliberately break
  * compatibility with old F1 code so there is no confusion with similar

include/libopencm3/stm32/f4/memorymap.h

@@ -22,7 +22,7 @@
 
 #include <libopencm3/cm3/memorymap.h>
 
-/* --- STM32F20x specific peripheral definitions ------------------------------- */
+/* --- STM32F4 specific peripheral definitions ----------------------------- */
 
 /* Memory map for all busses */
 #define PERIPH_BASE			0x40000000

include/libopencm3/stm32/f4/nvic_f4.h

@@ -22,7 +22,7 @@
 
 /* --- IRQ channel numbers-------------------------------------------------- */
 
-/* Note: These F2 specific user interrupt definitions supplement the
+/* Note: These F4 specific user interrupt definitions supplement the
  * general NVIC definitions in ../nvic.h
  */