vfs: hoist the btrfs deduplication ioctl to the vfs

Hoist the btrfs EXTENT_SAME ioctl up to the VFS and make the name
more systematic (FIDEDUPERANGE).

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/compat_ioctl.c b/fs/compat_ioctl.c
index 70d4b10..eab31e7 100644
--- a/fs/compat_ioctl.c
+++ b/fs/compat_ioctl.c
@@ -1582,6 +1582,7 @@
 
 	case FICLONE:
 	case FICLONERANGE:
+	case FIDEDUPERANGE:
 		goto do_ioctl;
 
 	case FIBMAP: