PCI: Fix devres regression in pci_intx()

PCI: Fix devres regression in pci_intx()

pci_intx() becomes managed if pcim_enable_device() has been called in
advance. Commit 25216afc9db5 ("PCI: Add managed pcim_intx()") changed this
behavior so that pci_intx() always leads to creation of a separate device
resource for itself, whereas earlier, a shared resource was used for all
PCI devres operations.

Unfortunately, pci_intx() seems to be used in some drivers' remove() paths;
in the managed case this causes a device resource to be created on driver
detach, which causes .probe() to fail if the driver is reloaded:

  pci 0000:00:1f.2: Resources present before probing

Fix the regression by only redirecting pci_intx() to its managed twin
pcim_intx() if the pci_command changes.

Link: https://lore.kernel.org/r/[email protected]
Fixes: 25216afc9db5 ("PCI: Add managed pcim_intx()")
Reported-by: Damien Le Moal <[email protected]>
Closes: https://lore.kernel.org/all/[email protected]/
Signed-off-by: Philipp Stanner <[email protected]>
[bhelgaas: add error message to commit log]
Signed-off-by: Bjorn Helgaas <[email protected]>
Tested-by: Damien Le Moal <[email protected]>