misc: pci_endpoint_test: Give reserved BARs a distinct error code

misc: pci_endpoint_test: Give reserved BARs a distinct error code

Give reserved BARs a distinct error code, such that the pci_endpoint_test
selftest will be able to skip test cases that are run against reserved
BARs.

Signed-off-by: Niklas Cassel <cassel@kernel.org>
[mani: Used __fls(CAP_BAR0_RESERVED) instead of PCI_ENDPOINT_CAP_BAR0_RESERVED_BIT]
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Tested-by: Manikanta Maddireddy <mmaddireddy@nvidia.com>
Tested-by: Koichiro Den <den@valinux.co.jp>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260312130229.2282001-21-cassel@kernel.org