iwlwifi: pcie: disable L1 Active after pci_enable_device

As Arjan pointed out, we mustn't do anything related to PCI
configuration until the device is properly enabled with
pci_enable_device().

Cc: stable@vger.kernel.org
Reported-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>