clocksource/drivers/arm_arch_timer: Advertise 56bit timer to the core code

Proudly tell the code code that we have a timer able to handle
56 bits deltas.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211017124225.3018098-9-maz@kernel.orgSigned-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

drivers/clocksource/arm_arch_timer.c

@@ -834,7 +834,7 @@ static void __arch_timer_setup(unsigned type,
 
 	clk->set_state_shutdown(clk);
 
-	clockevents_config_and_register(clk, arch_timer_rate, 0xf, 0x7fffffff);
+	clockevents_config_and_register(clk, arch_timer_rate, 0xf, CLOCKSOURCE_MASK(56));
 }
 
 static void arch_timer_evtstrm_enable(int divider)