dt-bindings: PCI: dw: rockchip: Add rk3576 support

dt-bindings: PCI: dw: rockchip: Add rk3576 support

rk3576 is using DWC PCIe controller, with msi interrupt directly to GIC
instead of using GIC ITS, so
- no ITS support is required and the 'msi-map' is not required,
- a new 'msi' interrupt is needed.

Co-developed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
[mani: changed 'its' to 'ITS' in the binding, spelling mistake fix]
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patch.msgid.link/20250414145110.11275-2-kever.yang@rock-chips.com