PCI: dw-rockchip: Rename rockchip_pcie_legacy_int_handler()

Rename the function rockchip_pcie_legacy_int_handler() to
rockchip_pcie_intx_handler() to match the code managing INTX interrupts
(e.g. intx_domain_ops) and the term used in the PCI specifications.

Link: https://lore.kernel.org/r/20231122060406.14695-12-dlemoal@kernel.org


Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>