x86/tsc: Annotate printouts as firmware bug

Make it more obvious that the BIOS is screwed up.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Roland Scheidegger <rscheidegger_lists@hispeed.ch>
Cc: Bruce Schlobohm <bruce.schlobohm@intel.com>
Cc: Kevin Stanton <kevin.b.stanton@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>