linux/mount.h: add atomic.h and spinlock.h #includes

I'm not sure what the current policy is on include files being self-sufficient, so feel free to drop this if we don't want to do this sort of cleanup...

<linux/mount.h> uses atomic_t and spinlock_t, but doesn't include either <asm/atomic.h> or <linux/spinlock.h>, which means that any users of <linux/mount.h> have to include them. This patch adds the necessary #includes to avoid this.

Index: linux-bk/include/linux/mount.h
===================================================================
@@ -13,6 +13,8 @@
 #ifdef __KERNEL__
 
 #include <linux/list.h>
+#include <linux/spinlock.h>
+#include <asm/atomic.h>
 
 #define MNT_NOSUID	1
 #define MNT_NODEV	2