ahci: mmio_base is a virtual address

Don't store it in a u32.

Don't dereference the bus address as if it were a virtual address
(fixes 284231e49a2b4 ("ahci: Support splitting of read transactions
into multiple chunks")).

Fixes crash on boot in MPC8641HPCN_36BIT target.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Cc: Vadim Bendebury <vbendeb@chromium.org>
Acked-by: York Sun <yorksun@freescale.com>
diff --git a/board/highbank/highbank.c b/board/highbank/highbank.c
index fc2385c..ba1beb5 100644
--- a/board/highbank/highbank.c
+++ b/board/highbank/highbank.c
@@ -57,7 +57,7 @@
 	u32 reg = readl(HB_SREG_A9_PWRDOM_STAT);
 
 	if (reg & PWRDOM_STAT_SATA) {
-		ahci_init(HB_AHCI_BASE);
+		ahci_init((void __iomem *)HB_AHCI_BASE);
 		scsi_scan(1);
 	}
 }