Better docs for boot-up code

Index: linux/arch/i386/boot/setup.S
===================================================================
@@ -893,6 +893,9 @@
 	movw	%cs, %si
 	subw	$DELTA_INITSEG, %si
 	shll	$4, %esi			# Convert to 32-bit pointer
+
+# jump to startup_32 in arch/i386/kernel/head.S
+#	
 # NOTE: For high loaded big kernels we need a
 #	jmpi    0x100000,__BOOT_CS
 #

Index: linux/arch/i386/kernel/trampoline.S
===================================================================
@@ -4,6 +4,8 @@
  *
  *	4 Jan 1997 Michael Chastain: changed to gnu as.
  *
+ *	This is only used for booting secondary CPUs in SMP machine
+ *
  *	Entry: CS:IP point to the start of our code, we are 
  *	in real mode with no stack, but the rest of the 
  *	trampoline page to make our stack and everything else