irqchip/irq-bcm7120-l2: Fix section mismatch

irqchip/irq-bcm7120-l2: Fix section mismatch

[ Upstream commit bfc0c5beab1fde843677923cf008f41d583c980a ]

Platform drivers can be probed after their init sections have been
discarded so the irqchip init callbacks must not live in init.

Fixes: 3ac268d5ed22 ("irqchip/irq-bcm7120-l2: Switch to IRQCHIP_PLATFORM_DRIVER")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>