Test: Correct delay function for FP interrupt test

Use osDelay instead of osDelayUntil, for osDelayUntil waits until
specified time which is not suitable for FP interrupt test.

Signed-off-by: Feder Liang <feder.liang@arm.com>
Change-Id: I6c96d17107a078963d952b397c9372118636f7f5
diff --git a/ns_interface/os_wrapper/delay.h b/ns_interface/os_wrapper/delay.h
index 9eaf95f..4242b81 100644
--- a/ns_interface/os_wrapper/delay.h
+++ b/ns_interface/os_wrapper/delay.h
@@ -15,12 +15,12 @@
 #include "common.h"
 
 /**
- * \brief Wait until an absolute time (specified in kernel ticks) is reached.
+ * \brief Waits for a time period specified in kernel ticks.
  *
  * \return \ref OS_WRAPPER_SUCCESS if the time delay is executed, or
  *         \ref OS_WRAPPER_ERROR in case of error
  */
-int32_t os_wrapper_delay_until(uint32_t ticks);
+int32_t os_wrapper_delay(uint32_t ticks);
 
 #ifdef __cplusplus
 }