iwlwifi: dvm: rename iwl_lib_ops to iwl_dvm_cfg

The next patches will move some more configuration
data that isn't needed by mvm into this struct, so
rename it now since it won't just be ops.

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