[openEuler-1.0-LTS] EHCI: Clear wakeup signal locked in S0 state when device plug in · Pull Request !89 · openEuler/kernel

If we plug in a LS/FS device on USB2 port of EHCI, it will latch a wakeup signal in EHCI internal. This is a bug of EHCI for Some project of ZhaoXin. If enable EHCI runtime suspend and no device attach. PM core will let EHCI go to D3 to save power. However, once EHCI go to D3, it will release wakeup signal that latched on device connect to port during S0. Which will generate a SCI interrupt and bring EHCI to D0. But without device connect, EHCI will go to D3 again. So, there is suspend-resume loop and generate SCI interrupt Continuously.

In order to fix this issues, we need to clear the wakeup signal latched in EHCI when EHCI suspend function is called.

### Issue
https://gitee.com/openeuler/kernel/issues/I54V1P

### Test
#### Plug test:
- Plug and unplug the device several times, and check whether it can be recognized normally.
#### RTD3 test:
1. Plug KB / mouse and unplug it
2. Enable EHCI RTD3 (Take EHCI's BDF[00:10.7] as an example: echo auto >/sys/bus/pci/devices/0000：00：10.7/power/control)
3. Watch –n.1 "cat /proc/interrupt | grep acpi" Check whether interrupts are increasing rapidly.
4. Plug device on USB2.0 port and check whether it is recognized.
#### Sx state test:
1. Let the system enter Sx state, Then Plug device to see if it can be recognized.
2. Let the system enter Sx state with device，Then, check whether the device can recognize after resume.

If the device can be correctly identified, the test can be considered as passed.

### Known Issue
N/A

### Default config change
N/A

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