clocksource/drivers/renesas-ostm: Use unique device name instead of ostm

Currently all OSTM devices are called "ostm", also in kernel messages.

As there can be multiple instances in an SoC, this can confuse the user.
Hence construct a unique name from the DT node name, like is done for
platform devices.

On RSK+RZA1, the boot log changes like:

    -clocksource: ostm: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 57352151442 ns
    +clocksource: timer@fcfec000: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 57352151442 ns
     sched_clock: 32 bits at 33MHz, resolution 30ns, wraps every 64440619504ns
    -ostm: used for clocksource
    -ostm: used for clock events
    +/soc/timer@fcfec000: used for clocksource
    +/soc/timer@fcfec400: used for clock events
     ...
    -clocksource: Switched to clocksource ostm
    +clocksource: Switched to clocksource timer@fcfec000
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20191016144747.29538-5-geert+renesas@glider.be

drivers/clocksource/renesas-ostm.c

@@ -64,9 +64,9 @@ static int __init ostm_init_clksrc(struct timer_of *to)
 	writeb(CTL_FREERUN, timer_of_base(to) + OSTM_CTL);
 	writeb(TS, timer_of_base(to) + OSTM_TS);
 
-	return clocksource_mmio_init(timer_of_base(to) + OSTM_CNT, "ostm",
-				     timer_of_rate(to), 300, 32,
-				     clocksource_mmio_readl_up);
+	return clocksource_mmio_init(timer_of_base(to) + OSTM_CNT,
+				     to->np->full_name, timer_of_rate(to), 300,
+				     32, clocksource_mmio_readl_up);
 }
 
 static u64 notrace ostm_read_sched_clock(void)
@@ -190,13 +190,13 @@ static int __init ostm_init(struct device_node *np)
 			goto err_cleanup;
 
 		ostm_init_sched_clock(to);
-		pr_info("ostm: used for clocksource\n");
+		pr_info("%pOF: used for clocksource\n", np);
 	} else {
 		ret = ostm_init_clkevt(to);
 		if (ret)
 			goto err_cleanup;
 
-		pr_info("ostm: used for clock events\n");
+		pr_info("%pOF: used for clock events\n", np);
 	}
 
 	return 0;