PCI: endpoint: Verify that requested BAR size is a power of two

PCI: endpoint: Verify that requested BAR size is a power of two

When allocating a BAR using pci_epf_alloc_space(), there are checks that
round up the size to a power of two.

However, there is no check in pci_epc_set_bar() which verifies that the
requested BAR size is a power of two.

Add a power of two check in pci_epc_set_bar(), so that we don't need to
add such a check in each and every PCI endpoint controller driver.

Link: https://lore.kernel.org/r/20241213143301.4158431-14-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>