staging: dwc2: remove some useless debug prints

This removes some debug prints from pci.c and makes platform.c and pci.c
a bit more similar again.

Signed-off-by: Matthijs Kooijman <matthijs@stdin.nl>
Acked-by: Paul Zimmerman <paulz@synopsys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>