x86/microcode: Issue update message only once

x86/microcode: Issue update message only once

This is especially annoying on large boxes:

  x86: Booting SMP configuration:
  .... node  #0, CPUs:          #1
  microcode: CPU1 microcode updated early to revision 0x428, date = 2014-05-29
     #2
  microcode: CPU2 microcode updated early to revision 0x428, date = 2014-05-29
     #3
  ...

so issue the update message only once.

$ grep microcode /proc/cpuinfo

shows whether every core got updated properly.

Reported-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Thomas Voegtle <tv@lio96.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1454499225-21544-6-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>