Revert "xhci: replace xhci_read_64() with readq()"

This reverts commit e8b373326d8efcaf9ec1da8b618556c89bd5ffc4.  Many xHCI
host controllers can only handle 32-bit addresses, and writing 64-bits
at a time causes them to fail.  Reading 64-bits at a time may also cause
them to return 0xffffffff, so revert this commit as well.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
diff --git a/drivers/usb/host/xhci-dbg.c b/drivers/usb/host/xhci-dbg.c
index b016d38..eb009a4 100644
--- a/drivers/usb/host/xhci-dbg.c
+++ b/drivers/usb/host/xhci-dbg.c
@@ -203,12 +203,12 @@
 				addr, (unsigned int)temp);
 
 	addr = &ir_set->erst_base;
-	temp_64 = readq(addr);
+	temp_64 = xhci_read_64(xhci, addr);
 	xhci_dbg(xhci, "  %p: ir_set.erst_base = @%08llx\n",
 			addr, temp_64);
 
 	addr = &ir_set->erst_dequeue;
-	temp_64 = readq(addr);
+	temp_64 = xhci_read_64(xhci, addr);
 	xhci_dbg(xhci, "  %p: ir_set.erst_dequeue = @%08llx\n",
 			addr, temp_64);
 }
@@ -412,7 +412,7 @@
 {
 	u64 val;
 
-	val = readq(&xhci->op_regs->cmd_ring);
+	val = xhci_read_64(xhci, &xhci->op_regs->cmd_ring);
 	xhci_dbg(xhci, "// xHC command ring deq ptr low bits + flags = @%08x\n",
 			lower_32_bits(val));
 	xhci_dbg(xhci, "// xHC command ring deq ptr high bits = @%08x\n",