hwc2: End uevent thread in hwc_close

uevent_next_event blocks until the next event from the
kernel, which we don't intend to handle when we're closing the
hwc session. Cancel the uevent thread during shutdown.

CRs-Fixed: 2013062
Bug: 34206930
Change-Id: Ib6c7d3af3c17aa010c37b94a9f4c846e19c7f091
1 file changed