cactus: ivy: Add sleep service

This service sleeps for a number of milliseconds.

Change-Id: Ib7f17142d22c8313dedc5f8037874bacbf8ed5f4
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
diff --git a/spm/common/sp_helpers.h b/spm/common/sp_helpers.h
index ab6415d..fb2d8ac 100644
--- a/spm/common/sp_helpers.h
+++ b/spm/common/sp_helpers.h
@@ -55,7 +55,7 @@
 void announce_test_start(const char *test_desc);
 void announce_test_end(const char *test_desc);
 
-/* Sleep for at least 'duration_sec' seconds then return. */
-void sp_sleep(uint32_t duration_sec);
+/* Sleep for at least 'ms' milliseconds. */
+void sp_sleep(uint32_t ms);
 
 #endif /* SP_HELPERS_H */