thermal: hisilicon: fix IRQ imbalance enabling

When register sensors into thermal zone during initialization phase, it
reports error for IRQ imbalance enabling:

[    2.040713] WARNING: at kernel/irq/manage.c:513
[    2.040719] Modules linked in:
[    2.040721]
[    2.040729] CPU: 1 PID: 804 Comm: irq/33-hisi_the Not tainted 4.5.0-rc4+ #505
[    2.040732] Hardware name: HiKey Development Board (DT)
[    2.040736] task: ffffffc03ae82580 ti: ffffffc0379c8000 task.ti: ffffffc0379c8000
[    2.040745] PC is at __enable_irq+0x74/0x84
[    2.040749] LR is at __enable_irq+0x74/0x84

This warning is for IRQ imbalance enabling, which is caused by
enable_irq() twice. During sensor's initialization it tries to enable
IRQ, the driver will call thermal_zone_of_sensor_register() to bind
sensors and read sensor's temperature. But at this moment the flag
"data->irq_enabled" has been not initialized as correct state, so it
finally introduces the function enabled_irq() to be called twice. In
essentially this is caused by the flag "data->irq_enabled" is
inconsistent with real hardware IRQ enabling state.

So this patch is to fix this issue, firstly init "irq_enabled" flag
before binding sensors to thermal zone. Also change to use the function
irq_get_irqchip_state() to read back real interrupt line state.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>