Blackfin: SMP: PERCPU section should be PAGE aligned

Common code checks the alignment of some of the variables and calls BUG()
if they aren't page aligned.
Signed-off-by: steven miao <realmz6@gmail.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

arch/blackfin/kernel/vmlinux.lds.S

@@ -136,7 +136,7 @@ SECTIONS
 
 	. = ALIGN(16);
 	INIT_DATA_SECTION(16)
-	PERCPU(32, 4)
+	PERCPU(32, PAGE_SIZE)
 
 	.exit.data :
 	{