os/board/rtl8730e/src: disable unnecessary IRQ when backlight power OFF

1. LCDC irq can be disabled when backlight power OFF
2. MIPI irq cannot be disabled because it is required to send cmd to turn backlight power ON, eg: ioctl(fd, LCDDEVIO_SETPOWER, x) where x >0

os/board/rtl8730e/src/rtl8730e_mipi_lcdc.c

@@ -81,6 +81,7 @@ struct irq {
 	u32 num;
 	u32 data;
 	u32 priority;
+	bool disable_isr;
 };
 
 LCDC_TypeDef *pLCDC = LCDC;
@@ -93,6 +94,7 @@ struct irq lcdc_irq_info = {
 	.num = LCDC_IRQ,
 	.data = (u32) LCDC,
 	.priority = INT_PRI_HIGH,
+	.disable_isr = 0,
 };
 
 extern struct irq mipi_irq_info;
@@ -206,6 +208,13 @@ static void rtl8730e_control_backlight(uint8_t level)
 	lcdvdbg("level :%d , pwm level:%f\n", level, pwm_level);
 #if defined(CONFIG_LCD_ST7785) || defined(CONFIG_LCD_ST7701SN)
 	pwmout_write(&g_rtl8730e_config_dev_s.pwm_led, 1.0-pwm_level);
+	if (level == 0 && !(lcdc_irq_info.disable_isr)) {
+		InterruptDis(lcdc_irq_info.num);
+		lcdc_irq_info.disable_isr = 1;
+	} else if (level != 0 && lcdc_irq_info.disable_isr) {
+		InterruptEn(lcdc_irq_info.num, lcdc_irq_info.priority);
+		lcdc_irq_info.disable_isr = 0;
+	}
 #endif
 }