ktest.pl: Fix typo in comment

"on of these" should be "one of these".

Fixes: 77d942c ("ktest: Create variables for the ktest config files")
Link: https://lore.kernel.org/20240902124645.5674-1-bajing@cmss.chinamobile.com
Signed-off-by: Ba Jing <bajing@cmss.chinamobile.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Author: Ba Jing

tools/testing/ktest/ktest.pl

@@ -1245,7 +1245,7 @@ sub __read_config {
 	    # Config variables are only active while reading the
 	    # config and can be defined anywhere. They also ignore
 	    # TEST_START and DEFAULTS, but are skipped if they are in
-	    # on of these sections that have SKIP defined.
+	    # one of these sections that have SKIP defined.
 	    # The save variable can be
 	    # defined multiple times and the new one simply overrides
 	    # the previous one.