x86: Change MMIO addr in readN(addr)/writeN(addr, val) to pointer

On x86, change the type of the address parameter in
read8()/read16/read32()/write8()/write16()/write32() to be a
pointer, instead of unsigned long.

Change-Id: Ic26dd8a72d82828b69be3c04944710681b7bd330
Signed-off-by: Kevin Paul Herbert <kph@meraki.net>
Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Reviewed-on: http://review.coreboot.org/7784
Tested-by: build bot (Jenkins)
diff --git a/src/include/device/pci_ehci.h b/src/include/device/pci_ehci.h
index 4d3f746..bd6b969 100644
--- a/src/include/device/pci_ehci.h
+++ b/src/include/device/pci_ehci.h
@@ -28,7 +28,7 @@
 #define PCI_EHCI_CLASSCODE 	0x0c0320	/* USB2.0 with EHCI controller */
 
 pci_devfn_t pci_ehci_dbg_dev(unsigned hcd_idx);
-unsigned long pci_ehci_base_regs(pci_devfn_t dev);
+u8 *pci_ehci_base_regs(pci_devfn_t dev);
 void pci_ehci_dbg_set_port(pci_devfn_t dev, unsigned int port);
 void pci_ehci_dbg_enable(pci_devfn_t dev, unsigned long base);