When the driver receives an event interrupt, the driver will enable
the event interrupt after handling all completed tasks on the function,
tasks on the function are parsed through only one thread. If the task's
user callback takes time, other tasks on the function will be blocked.

Therefore, the event irq processing is modified as follows:
1. Obtain the ID of the queue that completes the task.
2. Enable event interrupt.
3. Parse the completed tasks in the queue and call the user callback.
Enabling event interrupt in advance can quickly report pending event
interrupts and process tasks in multiple threads.
Signed-off-by: NWeili Qian <qianweili@huawei.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>