IB: Move the macro IB_UMEM_MAX_PAGE_CHUNK() to umem.c

After moving the definition of struct ib_umem_chunk from ib_verbs.h to
ib_umem.h there isn't any reason for the macro IB_UMEM_MAX_PAGE_CHUNK
to stay in ib_verbs.h.  Move the macro to umem.c, the only place where
it is used.

Signed-off-by: Dotan Barak <dotanb@dev.mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
index 26d0470..664d2faa 100644
--- a/drivers/infiniband/core/umem.c
+++ b/drivers/infiniband/core/umem.c
@@ -40,6 +40,11 @@
 
 #include "uverbs.h"
 
+#define IB_UMEM_MAX_PAGE_CHUNK						\
+	((PAGE_SIZE - offsetof(struct ib_umem_chunk, page_list)) /	\
+	 ((void *) &((struct ib_umem_chunk *) 0)->page_list[1] -	\
+	  (void *) &((struct ib_umem_chunk *) 0)->page_list[0]))
+
 static void __ib_umem_release(struct ib_device *dev, struct ib_umem *umem, int dirty)
 {
 	struct ib_umem_chunk *chunk, *tmp;