drivers/block/ahci: Fix pci mapping bug

The code assumes that the pci bus address and the virtual
address used to access a region are the same, but they might
not be.  Fix this assumption.

Signed-off-by: Becky Bruce <beckyb@kernel.crashing.org>

drivers/block/ahci.c

@@ -251,7 +251,6 @@ static void ahci_print_info(struct ahci_probe_ent *probe_ent)
 
 static int ahci_init_one(pci_dev_t pdev)
 {
-	u32 iobase;
 	u16 vendor;
 	int rc;
 
@@ -261,9 +260,6 @@ static int ahci_init_one(pci_dev_t pdev)
 	memset(probe_ent, 0, sizeof(struct ahci_probe_ent));
 	probe_ent->dev = pdev;
 
-	pci_read_config_dword(pdev, AHCI_PCI_BAR, &iobase);
-	iobase &= ~0xf;
-
 	probe_ent->host_flags = ATA_FLAG_SATA
 				| ATA_FLAG_NO_LEGACY
 				| ATA_FLAG_MMIO
@@ -272,7 +268,8 @@ static int ahci_init_one(pci_dev_t pdev)
 	probe_ent->pio_mask = 0x1f;
 	probe_ent->udma_mask = 0x7f;	/*Fixme,assume to support UDMA6 */
 
-	probe_ent->mmio_base = iobase;
+	probe_ent->mmio_base = (u32)pci_map_bar(pdev, AHCI_PCI_BAR,
+						PCI_REGION_MEM);
 
 	/* Take from kernel:
 	 * JMicron-specific fixup: