dtoc: Fix widening of int to bytes

At present an integer is converted to bytes incorrectly. The whole 32-bit
integer is inserted as the first element of the byte array, and the other
three bytes are skipped. This was not noticed because the unit test did
not check it, and the functional test was checking for wrong values.

Update the code to handle this as a special case. Add one more test to
cover all code paths.

Signed-off-by: Simon Glass <sjg@chromium.org>

test/py/tests/test_ofplatdata.py

@@ -20,7 +20,7 @@ byte 08
 bytearray 01 23 34
 int 3
 intarray 5 0 0 0
-longbytearray 09 00 00 00 00 00 00 00 00
+longbytearray 09 0a 0b 0c 00 00 00 00 00
 string message2
 stringarray "another" "multi-word" "message"
 of-platdata probe: