[testing] Rename ottf.h to ottf_main.h

Signed-off-by: Miguel Young de la Sota <mcyoung@google.com>
diff --git a/sw/device/tests/otbn_rsa_test.c b/sw/device/tests/otbn_rsa_test.c
index 95949e1..41a20f3 100644
--- a/sw/device/tests/otbn_rsa_test.c
+++ b/sw/device/tests/otbn_rsa_test.c
@@ -8,7 +8,7 @@
 #include "sw/device/lib/runtime/otbn.h"
 #include "sw/device/lib/testing/entropy_testutils.h"
 #include "sw/device/lib/testing/test_framework/check.h"
-#include "sw/device/lib/testing/test_framework/ottf.h"
+#include "sw/device/lib/testing/test_framework/ottf_main.h"
 
 #include "hw/top_earlgrey/sw/autogen/top_earlgrey.h"