Make ffb driver build on x86-64. The fix is two fold. First, use the

Make ffb driver build on x86-64.  The fix is two fold.  First, use the
proper DRM_CAS_RESULT to declare the variable used to store the result
of DRM_CAS.  Second, only use the "real" versions of LOCK_HARDWARE and
UNLOCK_HARDWARE on SPARC.  That's the only platform where the hardware
can really exist.