[patch-rt] rtmutex: Fix lock stealing logic

1. When trying to acquire an rtmutex, we first try to grab it without queueing the waiter, and explicitly check for that initial attempt in the !waiter path of __try_to_take_rt_mutex(). Checking whether the lock taker is top waiter before allowing a steal attempt in that path is a thinko: the

[patch-rt] rtmutex: Fix lock stealing logic

1. When trying to acquire an rtmutex, we first try to grab it without queueing the waiter, and explicitly check for that initial attempt in the !waiter path of __try_to_take_rt_mutex(). Checking whether the lock taker is top waiter before allowing a steal attempt in that path is a thinko: the