x86: standalone trampoline code

move the trampoline setup code out of smpboot.c - UP kernels can have
suspend support too.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/trampoline.c

@@ -0,0 +1,18 @@
+#include <linux/io.h>
+
+#include <asm/trampoline.h>
+
+/* ready for x86_64, no harm for x86, since it will overwrite after alloc */
+unsigned char *trampoline_base = __va(TRAMPOLINE_BASE);
+
+/*
+ * Currently trivial. Write the real->protected mode
+ * bootstrap into the page concerned. The caller
+ * has made sure it's suitably aligned.
+ */
+unsigned long setup_trampoline(void)
+{
+	memcpy(trampoline_base, trampoline_data,
+	       trampoline_end - trampoline_data);
+	return virt_to_phys(trampoline_base);
+}