iwlwifi: mvm: fix NVM check for 3168 devices

iwlwifi: mvm: fix NVM check for 3168 devices

BugLink: https://bugs.launchpad.net/bugs/1884089
[ Upstream commit b3f20e098293892388d6a0491d6bbb2efb46fbff ]

We had a check on !NVM_EXT and then a check for NVM_SDP in the else
block of this if.  The else block, obviously, could only be reached if
using NVM_EXT, so it would never be NVM_SDP.

Fix that by checking whether the nvm_type is IWL_NVM instead of
checking for !IWL_NVM_EXT to solve this issue.

Reported-by: Stefan Sperling <stsp@stsp.name>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>