tests: Fix ioctl data type

The `0xdeadbeef` constant in Vala is implicitly an int64. On 32 bit
big-endian architectures like powerpc this argument vanishes during its
interpretation through varargs and long (i.e. gets shifted to the second
argument, which we never look at). Explicitly make it an int.

tests/test-umockdev-vala.vala

@@ -1140,10 +1140,11 @@ E: SUBSYSTEM=test
   int fd = Posix.open ("/dev/test", Posix.O_RDWR, 0);
   assert_cmpint (fd, CompareOperator.GE, 0);
 
-  assert_cmpint (Posix.ioctl (fd, 1, 0xdeadbeef), CompareOperator.EQ, (int) 0xdeadbeef);
+  int value = (int) 0xdeadbeef;
+  assert_cmpint (Posix.ioctl (fd, 1, value), CompareOperator.EQ, value);
   assert_cmpint (Posix.errno, CompareOperator.EQ, 0);
 
-  assert_cmpint (Posix.ioctl (fd, 2, 0xdeadbeef), CompareOperator.EQ, -1);
+  assert_cmpint (Posix.ioctl (fd, 2, value), CompareOperator.EQ, -1);
   assert_cmpint (Posix.errno, CompareOperator.EQ, Posix.ENOMEM);
 
   assert_cmpint (Posix.ioctl (fd, 3, &ioctl_target), CompareOperator.EQ, 0);