aemfvp-a: updates for q1'24 release

Changes done to support AEMFVP-A-2024.04.15 release of the stack.
Modifications are
- update pci-hidden flag for model, earlier the virtio storage on the PCI
  bus modelling was broken so we were hiding it, disabling it now.
- update satadisk model parameter from pci.ahci_pci to pci.pcie_rc.ahci0
- update the artifact loading for fvp runs and use semihosting.

Signed-off-by: Ben Taylor <ben.taylor@linaro.org>
Change-Id: If4e6cf377bdb0f22bfee007f0ee1d432c9eb211c