xenbus: fix compile failure on ARM with Xen enabled

Adding an include of linux/mm.h resolves this:
	drivers/xen/xenbus/xenbus_client.c: In function ‘xenbus_map_ring_valloc_hvm’:
	drivers/xen/xenbus/xenbus_client.c:532:66: error: implicit declaration of function ‘page_to_section’ [-Werror=implicit-function-declaration]

CC: stable@vger.kernel.org
Signed-off-by: Steven Noonan <steven@uplinklabs.net>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
index bcf3ba4..61786be 100644 (file)
--- a/drivers/xen/xenbus/xenbus_client.c
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -30,6 +30,7 @@
  * IN THE SOFTWARE.
  */
 
+#include <linux/mm.h>
 #include <linux/slab.h>
 #include <linux/types.h>
 #include <linux/spinlock.h>