Initial FP exception flags incorrect on amd64

[das at FreeBSD.ORG (David Schultz)]

On Sat, Jun 05, 2004, Tim Robbins wrote:
> Apologies for the late response -- the new patch no longer causes panics
> on startup, and gives the expected results with your test program (0x00.)
> It doesn't seem to break any applications, but I don't do anything
> numerically intensive (X, KDE, Mozilla, compiling.)

Great!  Thanks, Tim.  If nothing catastrophic happened under a
normal workload, then resetting the CSR to its default value
probably didn't break anything.  I'll go ahead and commit the
patch.