selftests/ptrace: Fix spelling mistake "multible" -> "multiple"

Fix the spelling error from "multible" to "multiple".

Link: https://lore.kernel.org/r/20250501060329.126117-1-ankitchauhan2065@gmail.com
Signed-off-by: Ankit Chauhan <ankitchauhan2065@gmail.com>
Reviewed-by: Brigham Campbell <me@brighamcampbell.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Author: ankitchauhan2065

tools/testing/selftests/ptrace/peeksiginfo.c

@@ -199,7 +199,7 @@ int main(int argc, char *argv[])
 
 	/*
 	 * Dump signal from the process-wide queue.
-	 * The number of signals is not multible to the buffer size
+	 * The number of signals is not multiple to the buffer size
 	 */
 	if (check_direct_path(child, 1, 3))
 		goto out;