PCI: brcmstb: Remove chained IRQ handler and data in one go

Call irq_set_chained_handler_and_data() to clear the chained handler
and the handler's data under irq_desc->lock.

See also 2cf5a03c ("PCI/keystone: Fix race in installing chained
IRQ handler").

Link: https://lore.kernel.org/r/20210115211532.19837-1-martin@kaiser.cx


Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>