rdn2cfg1: add topologies for x4_0, x4_1, and x8 root complexes

Adding new topologies that add new devices for x4_0, x4_1, and x8 PCIe
root complexes. The topologies are configured to be in the same segment.
That means all the root complexes will have bus numbers and ECAM ranges
in continuation.

Signed-off-by: Nishant Sharma <nishant.sharma@arm.com>
Change-Id: I322f5e6301dc0ca342bf05b3a58b0831facbab95