drivers/timer/it51xxx: remove not used timer

Timer 7 is not used in timer driver, which means that timer
driver doesn't initialize timer 7, it's just declared in dtsi.
So I remove it, timer 7 will be used as alarm timer for counter driver.

Signed-off-by: Ruibin Chang <Ruibin.Chang@ite.com.tw>

Author: RuibinChang

drivers/timer/ite_it51xxx_timer.c

@@ -118,7 +118,7 @@ static volatile uint32_t last_elapsed;
 static volatile uint32_t last_ticks;
 
 #if defined(CONFIG_TEST)
-const int32_t z_sys_timer_irq_for_test = DT_IRQ_BY_IDX(DT_NODELABEL(timer), 4, irq);
+const int32_t z_sys_timer_irq_for_test = DT_IRQ_BY_IDX(DT_NODELABEL(timer), 3, irq);
 #endif
 
 static uint32_t read_timer_obser(enum ext_timer_idx timer_idx)

dts/riscv/ite/it51xxx.dtsi

@@ -1158,8 +1158,7 @@
 			interrupts = <IT51XXX_IRQ_TIMER3_DW IRQ_TYPE_EDGE_RISING   /* Event timer */
 				      IT51XXX_IRQ_TIMER4_DW IRQ_TYPE_EDGE_RISING   /* Free run */
 				      IT51XXX_IRQ_TIMER5_DW IRQ_TYPE_EDGE_RISING   /* Busy wait */
-				      IT51XXX_IRQ_TIMER6_DW IRQ_TYPE_EDGE_RISING   /* Busy wait */
-				      IT51XXX_IRQ_TIMER7_DW IRQ_TYPE_EDGE_RISING>;
+				      IT51XXX_IRQ_TIMER6_DW IRQ_TYPE_EDGE_RISING>; /* Busy wait */
 			interrupt-parent = <&intc>;
 		};