sparc64: correctly recognize SPARC64-X chips

The following patch adds support for correctly
recognizing SPARC-X chips.

cpu : Unknown SUN4V CPU
fpu : Unknown SUN4V FPU
pmu : Unknown SUN4V PMU

Signed-off-by: Katayama Yoshihiro <kata1@jp.fujitsu.com>
Signed-off-by: Allen Pais <allen.pais@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>