api: Add a header for api_init()

Put this in its own header instead of using common.h.

Signed-off-by: Simon Glass <sjg@chromium.org>

common/board_r.c

@@ -11,6 +11,7 @@
  */
 
 #include <common.h>
+#include <api.h>
 /* TODO: can we just include all these headers whether needed or not? */
 #if defined(CONFIG_CMD_BEDBUG)
 #include <bedbug/type.h>