PCI: dwc: ep: Rename dw_pcie_ep_exit() to dw_pcie_ep_deinit()

PCI: dwc: ep: Rename dw_pcie_ep_exit() to dw_pcie_ep_deinit()

dw_pcie_ep_exit() API is undoing what the dw_pcie_ep_init() API has done
already (at least partly). But the API name dw_pcie_ep_exit() is not quite
reflecting that. So let's rename it to dw_pcie_ep_deinit() to make the
purpose of this API clear. This also aligns with the DWC host driver.

Link: https://patchwork.kernel.org/project/linux-pci/patch/20240327-pci-dbi-rework-v12-4-082625472414@linaro.org
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>