PCI: endpoint: Introduce pci_epc_bar_type BAR_DISABLED

PCI: endpoint: Introduce pci_epc_bar_type BAR_DISABLED

Add a pci_epc_bar_type BAR_DISABLED to more clearly differentiate from
BAR_RESERVED.

This BAR type will only be used to describe a BAR that the EPC driver
should disable, and will thus never be available to an EPF driver.
(Unlike BAR_RESERVED, which will never be disabled by default by an EPC
driver.)

Co-developed-by: Manikanta Maddireddy <mmaddireddy@nvidia.com>
Signed-off-by: Manikanta Maddireddy <mmaddireddy@nvidia.com>
Signed-off-by: Niklas Cassel <cassel@kernel.org>
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Tested-by: Koichiro Den <den@valinux.co.jp>
Tested-by: Manikanta Maddireddy <mmaddireddy@nvidia.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Manikanta Maddireddy <mmaddireddy@nvidia.com>
Link: https://patch.msgid.link/20260312130229.2282001-17-cassel@kernel.org