ksmbd: fix r_count dec/increment mismatch
In the Linux kernel, the following vulnerability has been resolved:

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.