ARM: dts: msm: expand iommu-map to support PCIe switch on sdxprairie

Additional BDF to SID mappings are needed if a switch and
mutliple endpoints are connected to PCIe root complex.
Expand iommu-map for PCIe on sdxprarie to support such
a usecase.

Change-Id: I24585c603f913517e587048d10edbba4b4c9125a
Signed-off-by: Tony Truong <truong@codeaurora.org>