[PATCH] ktest: fix typo in comment

[Kathara Sasikumar]

Correct the spelling of "usefull" to "useful" in xapic_ipi_test comment.

Signed-off-by: Kathara Sasikumar <katharasasikumar007@xxxxxxxxx>
---
Hi,

Submitted as part of LFX Linux Kernel Mentorship (LKMP) task.
Thank you for your time and review.

Thanks,
Kathara

 tools/testing/selftests/kvm/x86/xapic_ipi_test.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/kvm/x86/xapic_ipi_test.c b/tools/testing/selftests/kvm/x86/xapic_ipi_test.c
index 35cb9de54a82..d7abf9a91b65 100644
--- a/tools/testing/selftests/kvm/x86/xapic_ipi_test.c
+++ b/tools/testing/selftests/kvm/x86/xapic_ipi_test.c
@@ -17,7 +17,7 @@
  * amongst the available numa nodes on the machine.
  *
  * Migration is a command line option. When used on non-numa machines will 
- * exit with error. Test is still usefull on non-numa for testing IPIs.
+ * exit with error. Test is still useful on non-numa for testing IPIs.
  */
 #include <getopt.h>
 #include <pthread.h>
-- 
2.47.2