usb: xhci: Make debug output better readable and checkpatch clean

This change makes debugging a bit easier as the output is better
readable with the added space. The explicit le16_to_cpu() is not
needed in the output. Also this patch moves the strings into one line
to make the patch checkpatch clean.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Aaron Williams <awilliams@marvell.com>
Cc: Chandrakala Chavva <cchavva@marvell.com>
Cc: Bin Meng <bmeng.cn@gmail.com>
Cc: Marek Vasut <marex@denx.de>