vt_kdsetmode: extend console locking

mainline inclusion
from mainline
commit 2287a51b
bugzilla: 181008 https://gitee.com/openeuler/kernel/issues/I4DDEL
CVE: CVE-2021-3753

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2287a51ba822384834dafc1c798453375d1107c7



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As per the long-suffering comment.

Reported-by: Minh Yuan <yuanmingbuaa@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Reviewed-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>