sparc: report "Unknown CPU/FPU" for unknown cpu/fpu

If we cannot determine the CPU or FPU report
"Unknown CPU" or "Unknown FPU" like sparc64 does.

And report with KERN_ERR that we cannot determine the CPU.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>