MFC r266782:

In r218101 I have not changed properly the futex syscall definition.
Some Linux futex ops atomically verifies that the futex address uaddr
(uval) contains the value val. Comparing signed uval and unsigned val
may lead to an unexpected result, mostly to a deadlock.

So copyin uaddr to an unsigned int to compare the parameters correctly.

While here change ktr records to print parameters in more readable format.

Approved by:	re (glebius)