usb: gadget: dwc: Avoid calling resume callback when remote wakeup fails

When _dwc3_gadget_wakeup() function is called, it initiates remote wakeup
to the USB HW, and then calls the resume interrupt handler simulate a
resume event. However, this should be done only if the remote wakeup has
succeeded. This patch fixes this issue.

Change-Id: I6a8296bebc2965f517bfad6eace58adc5780abb6
Signed-off-by: Danny Segal <dsegal@codeaurora.org>