PCI: j721e: Fix host/endpoint dependencies

PCI: j721e: Fix host/endpoint dependencies

The j721e driver has a single platform driver that can be built-in or a
loadable module, but it calls two separate backend drivers depending on
whether it is a host or endpoint.

If the two modes are not the same, we can end up with a situation where the
built-in pci-j721e driver tries to call the modular host or endpoint
driver, which causes a link failure:

  ld.lld-21: error: undefined symbol: cdns_pcie_ep_setup
  >>> referenced by pci-j721e.c
  >>>               drivers/pci/controller/cadence/pci-j721e.o:(j721e_pcie_probe) in archive vmlinux.a

  ld.lld-21: error: undefined symbol: cdns_pcie_host_setup
  >>> referenced by pci-j721e.c
  >>>               drivers/pci/controller/cadence/pci-j721e.o:(j721e_pcie_probe) in archive vmlinux.a

Rework the dependencies so that the 'select' is done by the common Kconfig
symbol, based on which of the two are enabled. Effectively this means that
having one built-in makes the other either built-in or disabled, but all
configurations will now build.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Siddharth Vadapalli <s-vadapalli@ti.com>
Link: https://patch.msgid.link/20250423162523.2060405-1-arnd@kernel.org