ext4: remove unused including <linux/version.h>

Remove including <linux/version.h> that don't need it.
Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Link: https://lore.kernel.org/r/1600397165-42873-1-git-send-email-tiantao6@hisilicon.comSigned-off-by: Theodore Ts'o <tytso@mit.edu>

fs/ext4/ext4.h

@@ -27,7 +27,6 @@
 #include <linux/seqlock.h>
 #include <linux/mutex.h>
 #include <linux/timer.h>
-#include <linux/version.h>
 #include <linux/wait.h>
 #include <linux/sched/signal.h>
 #include <linux/blockgroup_lock.h>