usb: dwc3: ep0: fix debug output

Use "ep0in" and "ep0out" instead "ep1in" and "ep0out" which is confusing
and not consistent with the remaining output.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>