parser,fdtQueryEngine: Fix parser bug with queries

When using dtb queries on a type that has multiple instances, when the
second or additional instances are evaluated, their settings have bad
values: `gpio_mux_server1.gpio.dtb = dtb({})` instead of the expected:
`gpio_mux_server1.gpio.dtb = dtb({"path" : "/gpio@2200000"})`.  This is
due to a parser bug that mutates the internal dictionary object instead
of mutating a copy.

Switching to a deep copy avoids mutating the AST object.

```
component GPIOMUXServer {

  emits FDT dummy_source;
  consumes FDT gpio;
  consumes FDT mux;

  composition {

    connection seL4DTBHardware gpio_conn(from dummy_source, to gpio);
    connection seL4DTBHardware mux_conn(from dummy_source, to mux);

  }

  configuration {
    gpio.dtb = dtb({"path" : "/gpio@2200000"});
    mux.dtb = dtb({"path" : "/pinmux@2430000"});

  }
}

assembly {
  composition {
    component GPIOMUXServer gpio_mux_server0;
    component GPIOMUXServer gpio_mux_server1;
  }
  configuration {}

}

```

Signed-off-by: Kent McLeod <[email protected]>

camkes/parser/fdtQueryEngine.py

@@ -10,6 +10,7 @@
 
 import functools
 import os
+import copy
 import six
 import re
 import logging
@@ -405,7 +406,12 @@ def _match_attr_dict(self, attr_dict):
 
     def query(self, attr):
         assert isinstance(attr, list)
-        return [self._match_attr_dict(attr_dict) for attr_dict in attr]
+
+        # Make a copy of each internal dict as _match_attr_dict mutates
+        # its arguments but we aren't allowed to mutate our arguments.
+        # Use deepcopy because the dict could contain more compound objects
+        # but can't contain recursive references.
+        return [self._match_attr_dict(copy.deepcopy(attr_dict)) for attr_dict in attr]
 
 
 class DtbMatchQuery(Query):