clocksource/drivers/timer-of: Use unique device name instead of timer

If a hardware-specific driver does not provide a name, the timer-of core
falls back to device_node.name.  Due to generic DT node naming policies,
that name is almost always "timer", and thus doesn't identify the actual
timer used.

Fix this by using device_node.full_name instead, which includes the unit
addrees.

Example impact on /proc/timer_list:

    -Clock Event Device: timer
    +Clock Event Device: timer@fcfec400
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20191016144747.29538-3-geert+renesas@glider.be

drivers/clocksource/timer-of.c

@@ -190,7 +190,7 @@ int __init timer_of_init(struct device_node *np, struct timer_of *to)
 	}
 
 	if (!to->clkevt.name)
-		to->clkevt.name = np->name;
+		to->clkevt.name = np->full_name;
 
 	to->np = np;