configs: Fix unconnected PCI port in SST gem5 config

PCI Host was added to the HiFive platform here,
https://gem5-review.googlesource.com/c/public/gem5/+/59969

This change connects the PCI host to the membus. However,
it will not be added to the device tree.

Change-Id: I2c1b1049597e5bfd0be467ef2a514d70bc2dd83e
Signed-off-by: Hoa Nguyen <hoanguyen@ucdavis.edu>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/60989
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/61734
Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu>
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
diff --git a/configs/example/sst/riscv_fs.py b/configs/example/sst/riscv_fs.py
index bdbd061..b5a6cc6 100644
--- a/configs/example/sst/riscv_fs.py
+++ b/configs/example/sst/riscv_fs.py
@@ -93,6 +93,8 @@
 
     system.platform = HiFive()
 
+    system.platform.pci_host.pio = system.membus.mem_side_ports
+
     system.platform.rtc = RiscvRTC(frequency=Frequency("100MHz"))
     system.platform.clint.int_pin = system.platform.rtc.int_pin