arm64: dts: fsl: ls1028a: Add PCI IERC node and ENETC endpoints

The LS1028A SoC features a PCI Integrated Endpoint Root Complex
(IERC) defining several integrated PCI devices, including the ENETC
ethernet controller integrated endpoints (IEPs). The IERC implements
ECAM (Enhanced Configuration Access Mechanism) to provide access
to the PCIe config space of the IEPs. This means the the IEPs
(including ENETC) do not support the standard PCIe BARs, instead
the Enhanced Allocation (EA) capability structures in the ECAM space
are used to fix the base addresses in the system, and the PCI
subsystem uses these structures for device enumeration and discovery.
The "ranges" entries contain basic information from these EA capabily
structures required by the kernel for device enumeration.

The current patch also enables the first 2 ENETC PFs (Physiscal
Functions) and the associated VFs (Virtual Functions), 2 VFs for
each PF.  Each of these ENETC PFs has an external ethernet port
on the LS1028A SoC.

Signed-off-by: Alex Marginean <alexandru.marginean@nxp.com>
Signed-off-by: Claudiu Manoil <claudiu.manoil@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>