[ion] Add Ion::crc32

Takes only 32bit values. Uses non-reversed data/input

Change-Id: I8a776064af69047f7a8fa1399cf8a484f42b9b18

ion/include/ion.h

@@ -8,6 +8,8 @@
 #include <ion/keyboard.h>
 #include <ion/led.h>
 #include <ion/power.h>
+#include <stdint.h>
+#include <string.h>
 
 
 /* ION is not your regular library. It is a library you link against, but it
@@ -26,6 +28,10 @@ void usleep(long us);
 /* CAUTION: This is a complete reset! */
 void reset();
 
+// CRC32 : non xor-ed, non reversed, direct, polynomial 4C11DB7
+// Only accepts whole 32bit values
+uint32_t crc32(const uint32_t * data, size_t length);
+
 }
 
 #endif