usb: dwc3: core: fix wrong OTG event regitser offset

This patch fixes the wrong OTG_EVT,OTG_EVTEN and OTG_STS register
offsets.

While at that, also add a missing register to debugfs regdump
utility.

Signed-off-by: George Cherian <george.cherian@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/dwc3/debugfs.c b/drivers/usb/dwc3/debugfs.c
index 8b23d045..9e9f122 100644
--- a/drivers/usb/dwc3/debugfs.c
+++ b/drivers/usb/dwc3/debugfs.c
@@ -372,6 +372,7 @@
 
 	dump_register(OCFG),
 	dump_register(OCTL),
+	dump_register(OEVT),
 	dump_register(OEVTEN),
 	dump_register(OSTS),
 };