The define for_each_pci_dev(d) is:
 while ((d = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, d)) != NULL)

Thus, the list iterator 'd' is always non-NULL so it doesn't need to
be checked. So just remove the unnecessary NULL check. Also remove the
unnecessary initializer because the list iterator is always initialized.
Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
Link: https://lore.kernel.org/r/20220406015921.29267-1-xiam0nd.tong@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>