sparc64: fix readout of cpu/fpu type

Meelis reported that on his box /proc/cpuinfo started
to reported "Unknow CPU" and the same did the boot messages.

It was a stupid bug I introduced when merging
cpu.c for 32 and 64 bit.

The code did an array reference where it had to search
for the right index.

Reported-by: Meelis Roos <mroos@linux.ee>
Tested-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>