i2c: validate user data in compat ioctl

stable inclusion
from stable-v4.19.224
commit 407c8708fb1bf2d4afc5337ef50635cf540c364b
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I947SE
CVE: CVE-2021-46934

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=407c8708fb1bf2d4afc5337ef50635cf540c364b



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[ Upstream commit bb436283 ]

Wrong user data may cause warning in i2c_transfer(), ex: zero msgs.
Userspace should not be able to trigger warnings, so this patch adds
validation checks for user data in compact ioctl to prevent reported
warnings

Reported-and-tested-by:  <syzbot+e417648b303855b91d8a@syzkaller.appspotmail.com>
Fixes: 7d5cb456 ("i2c compat ioctls: move to ->compat_ioctl()")
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>