m68k: Kill warning in setup_arch() when compiling for Sun3

arch/m68k/kernel/setup_mm.c: In function ‘setup_arch’:
arch/m68k/kernel/setup_mm.c:219: warning: unused variable ‘i’
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>

arch/m68k/kernel/setup_mm.c

@@ -216,7 +216,9 @@ static void __init m68k_parse_bootinfo(const struct bi_record *record)
 
 void __init setup_arch(char **cmdline_p)
 {
+#ifndef CONFIG_SUN3
 	int i;
+#endif
 
 	/* The bootinfo is located right after the kernel bss */
 	m68k_parse_bootinfo((const struct bi_record *)_end);