ceph: fix pr_fmt() redefinition

The vfs merge caused a latent bug to show up:

In file included from fs/ceph/super.h:4:0,
from fs/ceph/ioctl.c:3:
include/linux/ceph/ceph_debug.h:4:0: warning: "pr_fmt" redefined [enabled by default]
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
^
In file included from include/linux/kernel.h:13:0,
from include/linux/uio.h:12,
from include/linux/socket.h:7,
from include/uapi/linux/in.h:22,
from include/linux/in.h:23,
from fs/ceph/ioctl.c:1:
include/linux/printk.h:214:0: note: this is the location of the previous definition
#define pr_fmt(fmt) fmt
^

where the reason is that <linux/ceph_debug.h> is included much too late
for the "pr_fmt()" define.

The include of <linux/ceph_debug.h> needs to be the first include in the
file, but fs/ceph/ioctl.c had for some reason missed that, and it wasn't
noticeable until some unrelated header file changes brought in an
indirect earlier include of <linux/kernel.h>.

Signed-off-by: Linus Torvalds <[e-mail]>

fs/ceph/ioctl.c

···
+#include <linux/ceph/ceph_debug.h>
 #include <linux/in.h>
 
 #include "super.h"
 #include "mds_client.h"
-#include <linux/ceph/ceph_debug.h>
-
 #include "ioctl.h"