x86: Fix various typos in comments

Go over arch/x86/ and fix common typos in comments,
and a typo in an actual function argument name.

No change in functionality intended.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/events/intel/ds.c

@@ -1199,7 +1199,7 @@ static void setup_pebs_sample_data(struct perf_event *event,
 	/*
 	 * We must however always use iregs for the unwinder to stay sane; the
 	 * record BP,SP,IP can point into thin air when the record is from a
-	 * previous PMI context or an (I)RET happend between the record and
+	 * previous PMI context or an (I)RET happened between the record and
 	 * PMI.
 	 */
 	if (sample_type & PERF_SAMPLE_CALLCHAIN)