[SPARC64]: Do free_initmem() poisioning.

Just like on x86
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc64/mm/init.c

@@ -1745,6 +1745,7 @@ void free_initmem (void)
 		page = (addr +
 			((unsigned long) __va(kern_base)) -
 			((unsigned long) KERNBASE));
+		memset((void *)addr, 0xcc, PAGE_SIZE);
 		p = virt_to_page(page);
 
 		ClearPageReserved(p);