The new constant NVSXREG is defining the number of double word needed
to be save to get the remaining part of the VSX registers to be save.

A major part of the VSX registers is saved when saving FPU and Altivec
registers.
Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Reviewed-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>