usb: gadget: gsi: Ensure the doorbell is blocked before suspend

The doorbell is blocked as part of gsi_suspend, but a continuous
resume and suspend calls can cause a race where resume
handling overwrites the blocking of doorbell leading
to the controller accessing IPA doorbell after suspend.
Here are the series of events that is causing the issue.

gsi_resume
	queue_work with EVT_RESUME

gsi_suspend
	Block the doorbell
	queue_work with EVT_SUSPEND

resume_work_handler
	xdci_resume
	Unblock the doorbell

suspend_work_handler
	xdci_suspend

Fix this by ensuring that the doorbell is blocked
before suspend call to IPA as part of suspend handling.

Change-Id: I4d0254c88ed3bec6338d040480b5df2e3f81251e
Signed-off-by: Sriharsha Allenki <sallenki@codeaurora.org>