iwlwifi: remove useless iwl_free_nvm_data() function

This function just calls kfree(), so it only obscures the code without
bringing any benefits.  Remove it.

Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/ops.c b/drivers/net/wireless/intel/iwlwifi/mvm/ops.c
index 4e66cc6..fc2c607 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/ops.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/ops.c
@@ -849,7 +849,7 @@ static void iwl_op_mode_mvm_stop(struct iwl_op_mode *op_mode)
 	iwl_phy_db_free(mvm->phy_db);
 	mvm->phy_db = NULL;
 
-	iwl_free_nvm_data(mvm->nvm_data);
+	kfree(mvm->nvm_data);
 	for (i = 0; i < NVM_MAX_NUM_SECTIONS; i++)
 		kfree(mvm->nvm_sections[i].data);