x86/microcode/intel: Do not issue microcode updates messages on each CPU

On large systems the microcode driver is very noisy, because it prints a
line for each CPU. The lines are redundant because usually all CPUs are
updated to the same microcode revision.

All other subsystems have been patched previously to not print a line
for each CPU. Only the microcode driver is left.

Only print an microcode revision update when something changed. This
results in typically only a single line being printed.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: elliott@hpe.com
Cc: hmh@hmh.eng.br
Link: http://lkml.kernel.org/r/20160609134141.5981-1-andi@firstfloor.org


Signed-off-by: Ingo Molnar <mingo@kernel.org>