ksmbd: fix r_count dec/increment mismatch

ksmbd: fix r_count dec/increment mismatch

r_count is only increased when there is an oplock break wait,
so r_count inc/decrement are not paired. This can cause r_count
to become negative, which can lead to a problem where the ksmbd
thread does not terminate.

Fixes: 3aa660c05924 ("ksmbd: prevent connection release during oplock break notification")
Reported-by: Norbert Szetei <norbert@doyensec.com>
Tested-by: Norbert Szetei <norbert@doyensec.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>