MINOR: buffer: get rid of b_end() and b_to_end()

These ones are not used anymore.
diff --git a/include/common/buffer.h b/include/common/buffer.h
index c9868f0..0b768f2 100644
--- a/include/common/buffer.h
+++ b/include/common/buffer.h
@@ -73,18 +73,6 @@
 		__ret;                                          \
 	})
 
-/* Returns the pointer to the buffer's end (data+size) */
-static inline const char *b_end(const struct buffer *b)
-{
-	return b->data + b->size;
-}
-
-/* Returns the distance between <p> and the buffer's end (data+size) */
-static inline unsigned int b_to_end(const struct buffer *b)
-{
-	return b->data + b->size - b->p;
-}
-
 /* Return the buffer's length in bytes by summing the input and the output */
 static inline int buffer_len(const struct buffer *buf)
 {