sam3: Rename src/sam3x8e to src/sam3

This is in preparation for merging sam3 and sam4 code into one
directory.

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

src/sam3/internal.h

@@ -0,0 +1,13 @@
+#ifndef __SAM3_INTERNAL_H
+#define __SAM3_INTERNAL_H
+// Local definitions for sam3 code
+
+#include <stdint.h> // uint32_t
+
+#define GPIO(PORT, NUM) (((PORT)-'A') * 32 + (NUM))
+#define GPIO2PORT(PIN) ((PIN) / 32)
+#define GPIO2BIT(PIN) (1<<((PIN) % 32))
+
+void gpio_peripheral(uint32_t gpio, char ptype, int32_t pull_up);
+
+#endif // internal.h