pci: Show a message if PCI autoconfig fails

At present this fails silently which can be confusing since some devices
on the PCI bus may not work correctly. Show a message in this case.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
[bmeng: add a '\n' in the PCI autoconfig fail message]
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>