[PATCH v2 3/4] rtl8188eu: pwrctrl_priv: Replace semaphore 'lock' with mutex

The semaphore 'lock' in pwrctrl_priv is a simple mutex, so it should be written as one. Semaphores are going away in the future. _enter_pwrlock was using down_interruptible(), so the lock could be broken by sending a signal. This could be a bug, because nothing checks the return code here. Hence,

[PATCH v2 3/4] rtl8188eu: pwrctrl_priv: Replace semaphore 'lock' with mutex

The semaphore 'lock' in pwrctrl_priv is a simple mutex, so it should be written as one. Semaphores are going away in the future. _enter_pwrlock was using down_interruptible(), so the lock could be broken by sending a signal. This could be a bug, because nothing checks the return code here. Hence,