In newbus land, ivars can only be accessed for direct child, or when
the driver has unholy private knowledge of its great-*cgrandchildren.
The ACPI allocation routine lacked such knowledge when it tried to do
a default allocation for all descendants, rather than just its
immeidate children, so would access grandchild's ivar in an unsafe
way. This could lead to a panic when devices were present which had
no addresses setup by the BIOS, but which were later allocated in a
lazy manner via pci_alloc_map. As such, only do the default
allocation adjustments for immediate children. The manner that
acpi_sysres_find accesses the resource list, used later in
acpi_alloc_resource, is safe and proper so no additional test is
needed there.

This fixes a panic when probing an disabled ata controller on some
newer intel blades.

Reported by: dwhite