ksmbd: fix memory leak in parse_lease_state()

The previous patch that added bounds check for create lease context
introduced a memory leak. When the bounds check fails, the function
returns NULL without freeing the previously allocated lease_ctx_info
structure.

This patch fixes the issue by adding kfree(lreq) before returning NULL
in both boundary check cases.

Fixes: bab703ed ("ksmbd: add bounds check for create lease context")
Signed-off-by: Wang Zhaolong <wangzhaolong1@huawei.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>