iwlwifi: pcie: dump stack on NIC error in sync commands

Many times, a NIC error is the result of a bad command sent
to the device. If the command was sent synchronously, then
we'll currently print a message when the command is aborted
containing the command. It can be very useful to also see
the stack dump though, so also print that.
Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/iwlwifi/pcie/tx.c

@@ -1522,6 +1522,7 @@ static int iwl_pcie_send_hcmd_sync(struct iwl_trans *trans,
 	if (test_bit(STATUS_FW_ERROR, &trans_pcie->status)) {
 		IWL_ERR(trans, "FW error in SYNC CMD %s\n",
 			get_cmd_string(trans_pcie, cmd->id));
+		dump_stack();
 		ret = -EIO;
 		goto cancel;
 	}