PCI: endpoint: Allocate a 64-bit BAR if that is the only option

pci_epf_alloc_space() already sets the 64-bit flag if the BAR size is
larger than 2GB, even if the caller did not explicitly request a 64-bit
BAR.

Thus, let pci_epf_alloc_space() also set the 64-bit flag if the hardware
description says that the specific BAR can only be 64-bit.

Link: https://lore.kernel.org/linux-pci/20240320113157.322695-3-cassel@kernel.org


Signed-off-by: Niklas Cassel <cassel@kernel.org>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>