irqchip/vic: Fix a kernel-doc warning

Drop one extraneous struct member to quieten a warning:

drivers/irqchip/irq-vic.c:73: warning: Excess struct member 'parent_irq' description in 'vic_device'

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240221064104.7863-1-rdunlap@infradead.org