Extract container_of definition out of individual bindings

This will make possible reuse this portion on code in the future.

Testing: no change in functionality; compiles successfuly

Signed-off-by: Przemyslaw Czarnowski <przemyslaw.hawrylewicz.czarnowski@intel.com>
Change-Id: Ie92161c547e275d9aa00d643d8d4879d2f5dd199
diff --git a/serial.c b/serial.c
index f24148a..007a377 100644
--- a/serial.c
+++ b/serial.c
@@ -38,6 +38,7 @@
 #include "libmctp-alloc.h"
 #include "libmctp-log.h"
 #include "libmctp-serial.h"
+#include "container_of.h"
 
 struct mctp_binding_serial {
 	struct mctp_binding	binding;
@@ -67,11 +68,6 @@
 	uint8_t			txbuf[256];
 };
 
-#ifndef container_of
-#define container_of(ptr, type, member) \
-	(type *)((char *)(ptr) - (char *)&((type *)0)->member)
-#endif
-
 #define binding_to_serial(b) \
 	container_of(b, struct mctp_binding_serial, binding)