PCI: dw-rockchip: Remove unused PCIE_CLIENT_GENERAL_DEBUG definition

The PCIE_CLIENT_GENERAL_DEBUG register offset is defined but never
used in the driver. It's presence adds noise to the register map.

Remove this unused definition to keep the register list minimal and aligned
with actual hardware usage.

Signed-off-by: Hans Zhang <18255117159@163.com>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://patch.msgid.link/20250427125316.99627-2-18255117159@163.com