arm64: zynqmp: Add missing SMID for pcie to zynqmp.dtsi

The SMMU is disabled in device tree so this change has no impact.
The benefit is that this way it is in sync with xen.dtsi. Xen enables
the SMMU and makes use of it.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>