clocksource: arm_arch_timer: add a new enum for spi type

This patch add a new enum "arch_timer_spi_nr" and use it in the driver.
Just for code's readability, no functional change.

Signed-off-by: Fu Wei <fu.wei@linaro.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index 04218c1..15059c9 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -1258,9 +1258,9 @@
 	}
 
 	if (arch_timer_mem_use_virtual)
-		irq = irq_of_parse_and_map(best_frame, 1);
+		irq = irq_of_parse_and_map(best_frame, ARCH_TIMER_VIRT_SPI);
 	else
-		irq = irq_of_parse_and_map(best_frame, 0);
+		irq = irq_of_parse_and_map(best_frame, ARCH_TIMER_PHYS_SPI);
 
 	ret = -EINVAL;
 	if (!irq) {