PCI: dwc: Deallocate EPC memory on dw_pcie_ep_init() errors

PCI: dwc: Deallocate EPC memory on dw_pcie_ep_init() errors

If dw_pcie_ep_init() fails to perform any action after the EPC memory is
initialized and the MSI memory region is allocated, the latter parts won't
be undone thus causing a memory leak.  Add a cleanup-on-error path to fix
these leaks.

[bhelgaas: commit log]
Fixes: 900bd6cf43c3 ("PCI: designware-ep: Pre-allocate memory for MSI in dw_pcie_ep_init")
Link: https://lore.kernel.org/r/20220624143428.8334-6-Sergey.Semin@baikalelectronics.ru
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>