dev: Use recently added improvements to PME# support to simplify drivers

Depend on the PCI bus driver clearing PME# after resume to remove the
need for clearing PME# from DEVICE_RESUME methods.

Use pci_has_pm and pci_enable_pme.

Reviewed by: Krzysztof Galazka <krzysztof.galazka@intel.com>
Differential Revision: https://reviews.freebsd.org/D49251