PCI: cadence: Simplify J721e link status check

PCI: cadence: Simplify J721e link status check

Replace explicit if-else condition with direct return statement in
j721e_pcie_link_up(). This reduces code verbosity while maintaining
the same logic for detecting PCIe link completion.

Signed-off-by: Hans Zhang <18255117159@163.com>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Link: https://patch.msgid.link/20250510160710.392122-4-18255117159@163.com