If we boot up and find no hardware FPU we panic and die.

Change this behavior to be that if we boot up and we _expect_ a hardware
FPU to be present then panic. Don't panic if we don't actually expect to
have any hardware FPU.

This lets us compile a kernel without FPU if we really choose too.
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>