include/linux/dax.h: dax_iomap_fault() returns vm_fault_t

Commit 1c8f4220 ("mm: change return type to vm_fault_t") missed a
conversion.  It's not a big problem at present because mainline is still
using

	typedef int vm_fault_t;

Fixes: 1c8f4220 ("mm: change return type to vm_fault_t")
Link: http://lkml.kernel.org/r/20180620172046.GA27894@jordon-HP-15-Notebook-PCSigned-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/dax.h

@@ -135,7 +135,7 @@ void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);
 
 ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
 		const struct iomap_ops *ops);
-int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
+vm_fault_t dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
 		    pfn_t *pfnp, int *errp, const struct iomap_ops *ops);
 vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf,
 		enum page_entry_size pe_size, pfn_t pfn);