EHCI: Clear wakeup signal locked in S0 state when device plug in

zhaoxin inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I54V1P


CVE: NA

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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.

Signed-off-by: LeoLiu-oc <LeoLiu-oc@zhaoxin.com>