clocksource/drivers/imx-gpt: Add support for ARM64

This patch allows building and compile-testing the i.MX GPT driver
also for ARM64. The delay_timer is only supported on ARMv7.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

drivers/clocksource/Kconfig

@@ -567,7 +567,7 @@ config H8300_TPU
 
 config CLKSRC_IMX_GPT
 	bool "Clocksource using i.MX GPT" if COMPILE_TEST
-	depends on ARM && CLKDEV_LOOKUP
+	depends on (ARM || ARM64) && CLKDEV_LOOKUP
 	select CLKSRC_MMIO
 
 config CLKSRC_IMX_TPM

drivers/clocksource/timer-imx-gpt.c

@@ -141,21 +141,25 @@ static u64 notrace mxc_read_sched_clock(void)
 	return sched_clock_reg ? readl_relaxed(sched_clock_reg) : 0;
 }
 
+#if defined(CONFIG_ARM)
 static struct delay_timer imx_delay_timer;
 
 static unsigned long imx_read_current_timer(void)
 {
 	return readl_relaxed(sched_clock_reg);
 }
+#endif
 
 static int __init mxc_clocksource_init(struct imx_timer *imxtm)
 {
 	unsigned int c = clk_get_rate(imxtm->clk_per);
 	void __iomem *reg = imxtm->base + imxtm->gpt->reg_tcn;
 
+#if defined(CONFIG_ARM)
 	imx_delay_timer.read_current_timer = &imx_read_current_timer;
 	imx_delay_timer.freq = c;
 	register_current_timer_delay(&imx_delay_timer);
+#endif
 
 	sched_clock_reg = reg;