PCI: kirin: Don't discard .remove() callback

PCI: kirin: Don't discard .remove() callback

With CONFIG_PCIE_KIRIN=y and kirin_pcie_remove() marked with __exit, the
function is discarded from the driver. In this case a bound device can
still get unbound, e.g via sysfs. Then no cleanup code is run resulting in
resource leaks or worse.

The right thing to do is do always have the remove callback available.
This fixes the following warning by modpost:

  drivers/pci/controller/dwc/pcie-kirin: section mismatch in reference: kirin_pcie_driver+0x8 (section: .data) -> kirin_pcie_remove (section: .exit.text)

(with ARCH=x86_64 W=1 allmodconfig).

Fixes: 000f60db784b ("PCI: kirin: Add support for a PHY layer")
Link: https://lore.kernel.org/r/20231001170254.2506508-3-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org