usb: musb: restore INDEX register in resume path

commit 3c5fec75 upstream.

Restoring the missing INDEX register value in musb_restore_context().
Without this suspend resume functionality is broken with offmode
enabled.
Acked-by: Anand Gadiyar <gadiyar@ti.com>
Signed-off-by: Ajay Kumar Gupta <ajay.gupta@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/musb/musb_core.c

@@ -1634,6 +1634,7 @@ void musb_dma_completion(struct musb *musb, u8 epnum, u8 transmit)
 			}
 		}
 	}
+	musb_writeb(musb_base, MUSB_INDEX, musb->context.index);
 }
 
 #else