scripts/spelling.txt: add "an one" pattern and fix typo instances

Fix typos and add the following to the scripts/spelling.txt:

  an one||a one

I dropped the "an" before "one or more" in
drivers/net/ethernet/sfc/mcdi_pcol.h.

Link: http://lkml.kernel.org/r/1481573103-11329-6-git-send-email-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index 28d41e7..3abe337 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -951,7 +951,7 @@
 		if (rc == 0) {
 			/*
 			 * In case the new DSO is a duplicate of an existing
-			 * one, print an one-time warning & put the new entry
+			 * one, print a one-time warning & put the new entry
 			 * at the end of the list of duplicates.
 			 */
 			if (!dso || (dso == this))