Correct several assertions in the NTP test

Fixes:
```
>>> assert (pkt_1.precision.val == precision, pkt_1.precision.val)
Traceback (most recent call last):
  File "/usr/lib64/python3.11/codeop.py", line 153, in __call__
    return _maybe_compile(self.compiler, source, filename, symbol)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib64/python3.11/codeop.py", line 73, in _maybe_compile
    return compiler(source, filename, symbol)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib64/python3.11/codeop.py", line 118, in __call__
    codeob = compile(source, filename, symbol, self.flags, True)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<input>", line 2
SyntaxError: assertion is always true, perhaps remove parentheses?
```

test/scapy/layers/ntp.uts

@@ -1128,11 +1128,11 @@ assert (isinstance(pkt_1.orig, RawVal)), type(pkt_1.orig)
 assert (isinstance(pkt_1.sent, RawVal)), type(pkt_1.sent)
 assert (isinstance(pkt_1.recv, RawVal)), type(pkt_1.recv)
 
-assert (pkt_1.precision.val == precision, pkt_1.precision.val)
-assert (pkt_1.dispersion.val == dispersion, pkt_1.dispersion.val)
-assert (pkt_1.orig.val == time_stamp, pkt_1.orig.val)
-assert (pkt_1.sent.val == time_stamp, pkt_1.sent.val)
-assert (pkt_1.recv.val == time_stamp, pkt_1.recv.val)
+assert pkt_1.precision.val == precision, pkt_1.precision.val
+assert pkt_1.dispersion.val == dispersion, pkt_1.dispersion.val
+assert pkt_1.orig.val == time_stamp, pkt_1.orig.val
+assert pkt_1.sent.val == time_stamp, pkt_1.sent.val
+assert pkt_1.recv.val == time_stamp, pkt_1.recv.val
 
 time_stamp_hex = 0x00000000e67d6774
 pkt_2 = NTP(