usb: musb: dsps: add support for suspend and resume

The dsps platform needs to save save some registers at suspend time and
restore them after resume. This patch adds a struct for these registers,
and also lets the musb core know that the core registers need to be
saved as well.

We also have to explicitly de-assert the port reset upon resume on this
platform, but musb_port_reset() should not be called from glue layers.

Hence, introduce a flag in struct musb_hdrc_config for this.

Signed-off-by: Daniel Mack <zonque@gmail.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/musb/musb_host.c

@@ -2464,7 +2464,12 @@ static int musb_bus_suspend(struct usb_hcd *hcd)
 
 static int musb_bus_resume(struct usb_hcd *hcd)
 {
-	/* resuming child port does the work */
+	struct musb *musb = hcd_to_musb(hcd);
+
+	if (musb->config &&
+	    musb->config->host_port_deassert_reset_at_resume)
+		musb_port_reset(musb, false);
+
 	return 0;
 }