Move container_of() macro to stddef.h

It's not a SPI related macro, hence move it to stddef.h where
other similar macros live.

Change-Id: I1008894af7a272f1bc36d3ae6cee3881132b6ba9
Signed-off-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-on: http://review.coreboot.org/8109
Tested-by: build bot (Jenkins)
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>

src/include/spi_flash.h

@@ -28,17 +28,6 @@
 #include <console/console.h>
 #include <spi-generic.h>
 
-/**
- * container_of - cast a member of a structure out to the containing structure
- * @param ptr:    the pointer to the member.
- * @param type:   the type of the container struct this is embedded in.
- * @param member: the name of the member within the struct.
- *
- */
-#define container_of(ptr, type, member) ({			\
-	const typeof( ((type *)0)->member ) *__mptr = (ptr);	\
-	(type *)( (char *)__mptr - offsetof(type,member) );})
-
 struct spi_flash {
 	struct spi_slave *spi;
 

src/include/stddef.h

@@ -32,6 +32,17 @@ typedef unsigned int wint_t;
 	offsetof(struct structure, member) == offset, \
 	"`struct " #structure "` offset for `" #member "` is not " #offset )
 
+/**
+ * container_of - cast a member of a structure out to the containing structure
+ * @param ptr:    the pointer to the member.
+ * @param type:   the type of the container struct this is embedded in.
+ * @param member: the name of the member within the struct.
+ *
+ */
+#define container_of(ptr, type, member) ({			\
+	const typeof( ((type *)0)->member ) *__mptr = (ptr);	\
+	(type *)( (char *)__mptr - offsetof(type,member) );})
+
 #ifdef __PRE_RAM__
 #define ROMSTAGE_CONST const
 #else