[refcnt] Add ref_no_free handler

Since more reference-counted structures than embedded images might
want to mark themselves unfreeable, expose a dummy ref_no_free().

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/core/refcnt.c

 		free ( refcnt );
 	}
 }
+
+/**
+ * Do not free reference-counted object
+ *
+ * @v refcnt		Reference counter
+ *
+ * This is meant for initializing a reference counter structure in a
+ * statically allocated object.
+ */
+void ref_no_free ( struct refcnt *refcnt __unused ) {
+	/* Do nothing */
+}

src/image/embedded.c

 #include <ipxe/uaccess.h>
 #include <ipxe/init.h>
 
-/**
- * Free embedded image
- *
- * @v refcnt		Reference counter
- */
-static void __attribute__ (( unused ))
-embedded_image_free ( struct refcnt *refcnt __unused ) {
-	/* Do nothing */
-}
-
 /* Raw image data for all embedded images */
 #undef EMBED
 #define EMBED( _index, _path, _name )					\
 /* Image structures for all embedded images */
 #undef EMBED
 #define EMBED( _index, _path, _name ) {					\
-	.refcnt = REF_INIT ( embedded_image_free ),			\
+	.refcnt = REF_INIT ( ref_no_free ),				\
 	.name = _name,							\
 	.data = ( userptr_t ) ( embedded_image_ ## _index ## _data ),	\
 	.len = ( size_t ) embedded_image_ ## _index ## _len,		\

src/include/ipxe/refcnt.h

 
 extern struct refcnt * ref_get ( struct refcnt *refcnt );
 extern void ref_put ( struct refcnt *refcnt );
+extern void ref_no_free ( struct refcnt *refcnt );
 
 #endif /* _IPXE_REFCNT_H */