x86/events: Remove last remnants of old filenames

Update to the new file paths, remove them from introductory comments.

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20170218113140.8051-1-bp@alien8.de


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>