iwlwifi: mvm: allow setting the thermal state in D0i3

We were not allowing the thermal state to be set when we were in D0i3
mode.  It was not very clearly specified how it should work, but now a
decision was made to allow the state to be set in D0i3 (which will
cause a brief wake up).  Remove the check in the set_cur_state
operation.

Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>