dax: remove dax_pmd_fault()

dax_pmd_fault() is the old struct buffer_head + get_block_t based 2 MiB DAX
fault handler.  This fault handler has been disabled for several kernel
releases, and support for PMDs will be reintroduced using the struct iomap
interface instead.

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dave Chinner <david@fromorbit.com>

diff --git a/include/linux/dax.h b/include/linux/dax.h
index a41a747..0f74866 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -48,16 +48,12 @@ static inline int __dax_zero_page_range(struct block_device *bdev,
 }
 #endif
 
-#if defined(CONFIG_TRANSPARENT_HUGEPAGE)
-int dax_pmd_fault(struct vm_area_struct *, unsigned long addr, pmd_t *,
-				unsigned int flags, get_block_t);
-#else
 static inline int dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr,
 				pmd_t *pmd, unsigned int flags, get_block_t gb)
 {
 	return VM_FAULT_FALLBACK;
 }
-#endif
+
 int dax_pfn_mkwrite(struct vm_area_struct *, struct vm_fault *);
 #define dax_mkwrite(vma, vmf, gb)	dax_fault(vma, vmf, gb)