Debugger: Fix RegistersView context menu.

- Always grab the address value from the actual register value column,
  rather than the one that's in fact under the mouse. Fixes the "Inspect"
  item sending you to inspect address 0 if you happened to right click over
  the register name rather than the value.

src/apps/debugger/user_interface/gui/team_window/RegistersView.cpp

@@ -242,7 +242,7 @@ RegistersView::TableCellMouseDown(Table* table, int32 rowIndex,
 		return;
 
 	BVariant value;
-	if (!fRegisterTableModel->GetValueAt(rowIndex, columnIndex, value))
+	if (!fRegisterTableModel->GetValueAt(rowIndex, 1, value))
 		return;
 
 	BPopUpMenu* menu = new(std::nothrow)BPopUpMenu("Options");