block,fs: untangle fs.h and blk_types.h

Nothing in fs.h should require blk_types.h to be included.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index f0c7f14..efc953c 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1,4 +1,5 @@
 #include <linux/export.h>
+#include <linux/bvec.h>
 #include <linux/uio.h>
 #include <linux/pagemap.h>
 #include <linux/slab.h>