SMP: Add arch-agnostic boot_cpu()

We should not have x86 specific includes in lib/.

Change-Id: I18fa9c8017d65c166ffd465038d71f35b30d6f3d
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/5156
Tested-by: build bot (Jenkins)
Reviewed-by: David Hendricks <dhendrix@chromium.org>
Reviewed-by: Aaron Durbin <adurbin@google.com>
diff --git a/src/arch/x86/init/bootblock_simple.c b/src/arch/x86/init/bootblock_simple.c
index 204636e..34f55ca 100644
--- a/src/arch/x86/init/bootblock_simple.c
+++ b/src/arch/x86/init/bootblock_simple.c
@@ -1,3 +1,4 @@
+#include <smp/node.h>
 #include <bootblock_common.h>
 
 static void main(unsigned long bist)