powerpc: P1010RDB: Compile legacy PCIe routines conditionally

Compile the legacy PCIe initialization reoutines for P1010RDB
boards only when DM_PCI is not enabled.

Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>