powerpc: T208xQDS: Disable legacy PCIe driver when DM_PCI is enabled

Disable legacy PCIe driver and unused PCIe macros when DM_PCI enabled.

Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>