hugetlbfs: remove unneeded header file

The header file signal.h is unneeded now. Remove it.

Link: https://lkml.kernel.org/r/20220726142918.51693-4-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: MiaoheLin

fs/hugetlbfs/inode.c

@@ -11,7 +11,6 @@
 
 #include <linux/thread_info.h>
 #include <asm/current.h>
-#include <linux/sched/signal.h>		/* remove ASAP */
 #include <linux/falloc.h>
 #include <linux/fs.h>
 #include <linux/mount.h>