xfs: make xfs_file_remap_range() static

xfs_file_remap_range() is only used in fs/xfs/xfs_file.c, so make it
static.

This addresses a gcc warning when -Wmissing-prototypes is enabled.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

fs/xfs/xfs_file.c

@@ -920,7 +920,7 @@ out_unlock:
 }
 
 
-loff_t
+STATIC loff_t
 xfs_file_remap_range(
 	struct file		*file_in,
 	loff_t			pos_in,