x86: Add a dummy implementation for timer_get_us

The microsecond timer is not currently implemented, but add a dummy
implementation for now.

Signed-off-by: Gabe Black <gabeblack@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>

arch/x86/cpu/Makefile

@@ -30,7 +30,7 @@ LIB	= $(obj)lib$(CPU).o
 
 START-y	= start.o
 RESET_OBJS-$(CONFIG_X86_NO_RESET_VECTOR) += resetvec.o start16.o
-COBJS	= interrupts.o cpu.o
+COBJS	= interrupts.o cpu.o timer.o
 
 SRCS	:= $(START:.o=.S) $(SOBJS:.o=.S) $(COBJS:.o=.c)
 OBJS	:= $(addprefix $(obj),$(SOBJS) $(COBJS))

arch/x86/cpu/timer.c

@@ -0,0 +1,17 @@
+/*
+ * Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ */
+
+#include <common.h>
+
+unsigned long timer_get_us(void)
+{
+	printf("timer_get_us used but not implemented.\n");
+	return 0;
+}