irqchip/ti-sci-intr: Fix freeing of irqs

ti_sci_intr_irq_domain_free() assumes that out_irq of intr is stored in
data->chip_data and uses it for calling ti_sci irq_free() and then
mark the out_irq as available resource. But ti_sci_intr_irq_domain_alloc()
is storing p_hwirq(parent's hardware irq) which is translated from out_irq.
This is causing resource leakage and eventually out_irq resources might
be exhausted. Fix ti_sci_intr_irq_domain_alloc() by storing the out_irq
in data->chip_data.

Fixes: a5b659bd

 ("irqchip/ti-sci-intr: Add support for INTR being a parent to INTR")
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201102120631.11165-1-lokeshvutla@ti.com