csky/kprobe: reclaim insn_slot on kprobe unregistration

stable inclusion
from stable-v5.10.138
commit fa45327d8c52d82a680cbe48f81ff371a4408514
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I60QFD

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=fa45327d8c52d82a680cbe48f81ff371a4408514



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[ Upstream commit a2310c74 ]

On kprobe registration kernel allocate one insn_slot for new kprobe,
but it forget to reclaim the insn_slot on unregistration, leading to a
potential leakage.

Reported-by: Chen Guokai <chenguokai17@mails.ucas.ac.cn>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Liao Chang <liaochang1@huawei.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: Wei Li <liwei391@huawei.com>