The wakeup gen mask/unmask callback uses the irq element of the
irq_data to setup. The irq is the linux virtual irq number and
is same as the hardware irq number only when the parent irqchip
is setup as a legacy domain. When it is used as a linear domain,
the virtual irqs are allocated dynamically and wakeup gen code
cannot rely on these numbers to access the irq registers. Instead
use the hwirq element of the irq_data which represent the physical
irq number.

Cc: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Rajendra Nayak <rnayak@ti.com>
Cc: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sricharan R <r.sricharan@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>