MdeModulePkg/Bus/Pci/PciBusDxe: Support platform PCI ROM override

MdeModulePkg/Bus/Pci/PciBusDxe: Support platform PCI ROM override

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3811

Remove ASSERT() statements that are triggered if a platform provides
an override of PCI ROM attached to a PCI Controller.  The PCI Platform
Protocol allows the platform to provide a PCI ROM image for a PCI
Controller.  This works for PCI Controllers that do not have an attached
PCI ROM, but the platform is not allowed to replace the PCI ROM for a
PCI Controller that has its own PCI ROM.  Removing these ASSERT()
statements enables this additional use case.

Cc: Hao A Wu <hao.a.wu@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>