KVM: PPC: booke: standard PPC floating point support

e500mc has a normal PPC FPU, rather than SPE which is found
on e500v1/v2.

Based on code from Liu Yu <yu.liu@freescale.com>.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>