thermal/drivers/hisi: Fix missing interrupt enablement

The interrupt for the temperature threshold is not enabled at the end of the
probe function, enable it after the setup is complete.

On the other side, the irq_enabled is not correctly set as we are checking if
the interrupt is masked where 'yes' means irq_enabled=false.

	irq_get_irqchip_state(data->irq, IRQCHIP_STATE_MASKED,
				&data->irq_enabled);

As we are always enabling the interrupt, it is pointless to check if
the interrupt is masked or not, just set irq_enabled to 'true'.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Leo Yan <leo.yan@linaro.org>
Tested-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>