genirq/migration: Use irqd_get_parent_data() in irq_force_complete_move()

Frank reported, that the common irq_force_complete_move() breaks the out of
tree build of ia64. The reason is that ia64 uses the migration code, but
does not have hierarchical interrupt domains enabled.

This went unnoticed in mainline as both x86 and RISC-V have hierarchical
domains enabled. Not that it matters for mainline, but it's still
inconsistent.

Use irqd_get_parent_data() instead of accessing the parent_data field
directly. The helper returns NULL when hierarchical domains are disabled
otherwise it accesses the parent_data field of the domain.

No functional change.

Fixes: 751dc837 ("genirq: Introduce common irq_force_complete_move() implementation")
Reported-by: Frank Scheiner <frank.scheiner@web.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Frank Scheiner <frank.scheiner@web.de>
Link: https://lore.kernel.org/all/87h634ugig.ffs@tglx