usb: dwc3: add newlines to dev_vdbg calls in ep0

For some reason none of these debug prints have newlines, resulting in a
"fun" surprise when attempting to debug this driver.

The other parts of the dwc3 driver have newlines, add them here too (and
fix some minor nearby indent issues to make checkpatch happy).

Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>
Reviewed-by: Marek Vasut <marex@denx.de>