iwlwifi: mei: fix potential NULL-ptr deref

If SKB allocation fails, continue rather than using the NULL
pointer.

Coverity CID: 1497650

Cc: stable@vger.kernel.org
Fixes: 2da4366f ("iwlwifi: mei: add the driver to allow cooperation with CSME")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20220517120045.90c1b1fd534e.Ibb42463e74d0ec7d36ec81df22e171ae1f6268b0@changeid


Signed-off-by: Johannes Berg <johannes.berg@intel.com>