Blackfin: make sure percpu section is aligned in XIP builds

The alignment is normally handled by PERCPU(), but we need to do it
ourselves in the XIP build due to the custom layout.
Signed-off-by: Steven Miao <realmz6@gmail.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

arch/blackfin/kernel/vmlinux.lds.S

@@ -155,6 +155,7 @@ SECTIONS
 		SECURITY_INITCALL
 		INIT_RAM_FS
 
+		. = ALIGN(PAGE_SIZE);
 		___per_cpu_load = .;
 		PERCPU_INPUT(32)