xfs: kill xfs_vnode.h

Move the IO flag definitions to xfs_inode.h and kill the header file
as it is now empty.

Removing the xfs_vnode.h file showed up an implicit header include
path:
	xfs_linux.h -> xfs_vnode.h -> xfs_fs.h

And so every xfs header file has been inplicitly been including
xfs_fs.h where it is needed or not. Hence the removal of xfs_vnode.h
causes all sorts of build issues because BBTOB() and friends are no
longer automatically included in the build. This also gets fixed.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>

diff --git a/fs/xfs/xfs_linux.h b/fs/xfs/xfs_linux.h
index f59b966..f76e44e 100644
--- a/fs/xfs/xfs_linux.h
+++ b/fs/xfs/xfs_linux.h
@@ -113,7 +113,7 @@
 #include <asm/byteorder.h>
 #include <asm/unaligned.h>
 
-#include "xfs_vnode.h"
+#include "xfs_fs.h"
 #include "xfs_stats.h"
 #include "xfs_sysctl.h"
 #include "xfs_iops.h"