m68k: fix a compiler warning when building for DragonBall

In file included from arch/m68k/kernel/setup.c:4:0:
arch/m68k/kernel/setup_no.c:70:0: warning: "CPU_NAME" redefined [enabled by default]
 #define CPU_NAME "MC68VZ328"
 ^
arch/m68k/kernel/setup_no.c:61:0: note: this is the location of the previous definition
 #define CPU_NAME "MC68000"
 ^

Signed-off-by: Daniel Palmer <danieruru@gmail.com>
Signed-off-by: Greg Ungerer <gerg@uclinux.org>