PCI/ACPI: Skip _OSC control tests if _OSC support call failed

If the _OSC support notification fails, we will never request control
(because "support == OSC_PCI_SEGMENT_GROUPS_SUPPORT", which doesn't include
all the features in ACPI_PCIE_REQ_SUPPORT), so we can return early to
simplify the code.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>