usb: dwc3: core: Prevent USB core invalid event buffer address access

In the Linux kernel, the following vulnerability has been resolved: usb: dwc3: core: Prevent USB core invalid event buffer address access This commit addresses an issue where the USB core could access an invalid event buffer address during runtime suspend, potentially causing SMMU faults and other memory issues in Exynos platforms. The problem arises from the following sequence. 1. In dwc3_gadget_suspend, there is a chance of a timeout when moving the USB core to the halt state after clearing the run/stop bit by software. 2. In dwc3_core_exit, the event buffer is cleared regardless of the USB core's status, which may lead to an SMMU faults and other memory issues. if the USB core tries to access the event buffer address. To prevent this hardware quirk on Exynos platforms, this commit ensures that the event buffer address is not cleared by software when the USB core is active during runtime suspend by checking its status before clearing the buffer address.