sam3: Merge sam4e8e support into sam3 code

Most of the peripherals on the sam4e8e are similar to the ones on the
sam3x8e mcu.  Merge the code together and use just one code directory.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

src/sam3/internal.h

@@ -1,8 +1,15 @@
 #ifndef __SAM3_INTERNAL_H
 #define __SAM3_INTERNAL_H
-// Local definitions for sam3 code
+// Local definitions for sam3/sam4 code
 
 #include <stdint.h> // uint32_t
+#include "autoconf.h" // CONFIG_MACH_SAM3X8E
+
+#if CONFIG_MACH_SAM3X8E
+#include "sam3x8e.h"
+#elif CONFIG_MACH_SAM4E8E
+#include "sam4e.h"
+#endif
 
 #define GPIO(PORT, NUM) (((PORT)-'A') * 32 + (NUM))
 #define GPIO2PORT(PIN) ((PIN) / 32)