Pull x86 debug update from Ingo Molnar:
 "Two small changes: a documentation update and a constification"

* 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, early-printk: Update earlyprintk documentation (and kill x86 copy)
  x86: Constify a few items