PCI: dwc: ep: Return -ENOMEM for allocation failures

If the bitmap or memory allocations fail, then dw_pcie_ep_init_registers()
will incorrectly return a success.

Return -ENOMEM instead.

Fixes: 869bc52 ("PCI: dwc: ep: Fix DBI access failure for drivers requiring refclk from host")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
[kwilczynski: commit log]
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Krzysztof Wilczyński <kw@linux.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/36dcb6fc-f292-4dd5-bd45-a8c6f9dc3df7@stanley.mountain

Author: Dan Carpenter

drivers/pci/controller/dwc/pcie-designware-ep.c

@@ -774,6 +774,7 @@ int dw_pcie_ep_init_registers(struct dw_pcie_ep *ep)
 	if (ret)
 		return ret;
 
+	ret = -ENOMEM;
 	if (!ep->ib_window_map) {
 		ep->ib_window_map = devm_bitmap_zalloc(dev, pci->num_ib_windows,
 						       GFP_KERNEL);