arc: use timer driver for ARC boards

This commit replaces legacy timer code with usage of arc timer
driver.

It removes arch/arc/lib/time.c file and selects CONFIG_CLK,
CONFIG_TIMER and CONFIG_ARC_TIMER options for all ARC boards by default.
Therefore we remove CONFIG_CLK option from less common axs101 and
axs103 defconfigs.

Also it removes legacy CONFIG_SYS_TIMER_RATE config symbol from
axs10x.h, tb100.h and nsim.h configs files as it is no longer required.

Signed-off-by: Vlad Zakharov <vzakhar@synopsys.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

arch/Kconfig

@@ -13,6 +13,9 @@ config ARC
 	select HAVE_PRIVATE_LIBGCC
 	select SUPPORT_OF_CONTROL
 	select ARCH_EARLY_INIT_R
+	select CLK
+	select TIMER
+	select ARC_TIMER
 
 config ARM
 	bool "ARM architecture"

arch/arc/lib/Makefile

@@ -18,7 +18,6 @@ obj-y += memcmp.o
 obj-y += memcpy-700.o
 obj-y += memset.o
 obj-y += reset.o
-obj-y += timer.o
 obj-y += ints_low.o
 obj-y += init_helpers.o
 

arch/arc/lib/timer.c

@@ -1,24 +0,0 @@
-/*
- * Copyright (C) 2013-2014 Synopsys, Inc. All rights reserved.
- *
- * SPDX-License-Identifier:	GPL-2.0+
- */
-
-#include <asm/arcregs.h>
-
-#define NH_MODE	(1 << 1)	/* Disable timer if CPU is halted */
-
-int timer_init(void)
-{
-	write_aux_reg(ARC_AUX_TIMER0_CTRL, NH_MODE);
-	/* Set max value for counter/timer */
-	write_aux_reg(ARC_AUX_TIMER0_LIMIT, 0xffffffff);
-	/* Set initial count value and restart counter/timer */
-	write_aux_reg(ARC_AUX_TIMER0_CNT, 0);
-	return 0;
-}
-
-unsigned long timer_read_counter(void)
-{
-	return read_aux_reg(ARC_AUX_TIMER0_CNT);
-}