f2fs: avoid format-overflow warning

stable inclusion
from stable-v6.6.3
commit 3eebe636cac53886bd5d1cdd55e082ec9e84983f
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8LBQP

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3eebe636cac53886bd5d1cdd55e082ec9e84983f



--------------------------------

commit e0d4e8acb3789c5a8651061fbab62ca24a45c063 upstream.

With gcc and W=1 option, there's a warning like this:

fs/f2fs/compress.c: In function ‘f2fs_init_page_array_cache’:
fs/f2fs/compress.c:1984:47: error: ‘%u’ directive writing between
1 and 7 bytes into a region of size between 5 and 8
[-Werror=format-overflow=]
 1984 |  sprintf(slab_name, "f2fs_page_array_entry-%u:%u", MAJOR(dev),
		MINOR(dev));
      |                                               ^~

String "f2fs_page_array_entry-%u:%u" can up to 35. The first "%u" can up
to 4 and the second "%u" can up to 7, so total size is "24 + 4 + 7 = 35".
slab_name's size should be 35 rather than 32.

Cc: stable@vger.kernel.org
Signed-off-by: Su Hui <suhui@nfschina.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>