Documentation: devres: fix error about PCI devres

Documentation: devres: fix error about PCI devres

The documentation states that pcim_enable_device() will make "all PCI
ops" managed. This is totally false, only a small subset of PCI
functions become managed that way. Implicating otherwise has caused at
least one bug so far, namely in commit 8558de401b5f ("drm/vboxvideo: use
managed pci functions").

Change the function summary so the functions dangerous behavior becomes
obvious.

Signed-off-by: Philipp Stanner <pstanner@redhat.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240809095248.14220-2-pstanner@redhat.com