hv: vPCI: cache PCI BAR physical base address

PCI BAR physical base address will never changed. Cache it to avoid calculating
it every time when we access it.

Tracked-On: #3475
Signed-off-by: Li, Fei1 <fei1.li@intel.com>
Acked-by: Eddie Dong <eddie.dong@Intel.com>

hypervisor/hw/pci.c

@@ -288,6 +288,7 @@ static uint32_t pci_pdev_read_bar(union pci_bdf bdf, uint32_t idx, struct pci_ba
 	}
 
 	bar->size = size;
+	bar->base_hpa = base;
 
 	return (type == PCIBAR_MEM64)?2U:1U;
 }