DVDInterface: Initialize variables
JIT: add 64-bit write support to FIFO functions

Also fix 64-bit values passed to CallAC and otherwise correct immediate
handling in FIFO writes.
Fixes 007 Nightfire.
Merge pull request #1520 from JosJuice/dvdinterface-init

DVDInterface: Initialize variables
Merge pull request #1523 from FioraAeterna/fifo64

JIT: add 64-bit write support to FIFO functions and fix immediates