Revert r274635 as it's completely wrong.
The parent of a pci dev device is a pciX device which do not
implement the PCIB_POWER_FOR_SLEEP method from pcib_if.m.


git-svn-id: svn+ssh://svn.freebsd.org/base/head@274707 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f