iwlwifi: move some PCIe calls to better places

Synchronizing the IRQ is pointless when we will
then enable the RF-Kill interrupt again, but is
needed before we free it and the data needed to
handle IRQs; move it to the free function.

Simiarly, cancelling the replenish work struct
can move to the function that frees the RX data
structures.

Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>