PCI: Fix PCIe capability sizes

PCI_CAP_EXP_ENDPOINT_SIZEOF_V1 defines the size of the PCIe capability
structure for v1 devices with link, but we also have a need in the vfio
code for sizing the capability for devices without link, such as Root
Complex Integrated Endpoints.  Create a separate define for this ending the
structure before the link fields.

Additionally, this reveals that PCI_CAP_EXP_ENDPOINT_SIZEOF_V2 is currently
incorrect, ending the capability length before the v2 link fields.  Rename
this to specify an RC Integrated Endpoint (no link) capability length and
move PCI_CAP_EXP_ENDPOINT_SIZEOF_V2 to include the link fields as we have
for the v1 version.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
[bhelgaas: add "_" in "PCI_CAP_EXP_RC ENDPOINT_SIZEOF_V2 44"]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>