iwlwifi: pcie: Fix bug in NIC's PM registers access

While cleanig the access to those hw-dependent registers,
instead of using the product family type, wrong condition was added
mistakenly and enabled 8000 family devices a forbidden access
to HW registers, fix it.

Fixes: 95411d04 ("iwlwifi: pcie: Control access to the NIC's PM registers via iwl_cfg")
Signed-off-by: Dreyfuss, Haim <haim.dreyfuss@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>