canserial: Rename canbus.c to canserial.c

Rename the canbus.c code to canserial.c and introduce new wrapper
functions in canbus.c that connect the low-level canbus hardware code
to the high-level canserial.c code.

This is in preparation for adding "usb to canbus bridge mode".

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

src/generic/canserial.h

@@ -0,0 +1,19 @@
+#ifndef __CANSERIAL_H__
+#define __CANSERIAL_H__
+
+#include <stdint.h> // uint32_t
+
+#define CANBUS_ID_ADMIN 0x3f0
+#define CANBUS_ID_ADMIN_RESP 0x3f1
+
+// callbacks provided by board specific code
+struct canbus_msg;
+int canserial_send(struct canbus_msg *msg);
+void canserial_set_filter(uint32_t id);
+
+// canserial.c
+void canserial_notify_tx(void);
+void canserial_process_data(struct canbus_msg *msg);
+void canserial_set_uuid(uint8_t *raw_uuid, uint32_t raw_uuid_len);
+
+#endif // canbus.h