libpayload: Drop obsolete setting of reg_base in [oex]hci

Setting of `controller->reg_base` is of no use here, as it is never read
(in another function) later. Looks like this pattern originated from uhci.c
where it makes sense.

By removing the indirection through `reg_base` we also fix a possible
truncation to u32.

Change-Id: I5c99c5bf1f5b1d6c04bd84d87fd3e275fd7d0411
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: http://review.coreboot.org/6251
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
diff --git a/payloads/libpayload/drivers/usb/xhci.c b/payloads/libpayload/drivers/usb/xhci.c
index 69ddab7..0bd54c7 100644
--- a/payloads/libpayload/drivers/usb/xhci.c
+++ b/payloads/libpayload/drivers/usb/xhci.c
@@ -193,13 +193,11 @@
 		goto _free_xhci;
 	}
 
-	controller->reg_base	= (u32)physical_bar;
-
-	xhci->capreg	= phys_to_virt(controller->reg_base);
+	xhci->capreg	= phys_to_virt(physical_bar);
 	xhci->opreg	= ((void *)xhci->capreg) + xhci->capreg->caplength;
 	xhci->hcrreg	= ((void *)xhci->capreg) + xhci->capreg->rtsoff;
 	xhci->dbreg	= ((void *)xhci->capreg) + xhci->capreg->dboff;
-	xhci_debug("regbase: 0x%"PRIx32"\n", controller->reg_base);
+	xhci_debug("regbase: 0x%"PRIx32"\n", physical_bar);
 	xhci_debug("caplen:  0x%"PRIx32"\n", xhci->capreg->caplength);
 	xhci_debug("rtsoff:  0x%"PRIx32"\n", xhci->capreg->rtsoff);
 	xhci_debug("dboff:   0x%"PRIx32"\n", xhci->capreg->dboff);