SPM-MM: Fix call preemption test

The timer was being set up for 1 ms rather than 1 second.

Change-Id: I16d6ea69d42abf28dc9591e97d6bfb302d5f8127
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
diff --git a/spm/cactus_mm/cactus_mm_service_loop.c b/spm/cactus_mm/cactus_mm_service_loop.c
index 0ad60b6..dbec190 100644
--- a/spm/cactus_mm/cactus_mm_service_loop.c
+++ b/spm/cactus_mm/cactus_mm_service_loop.c
@@ -43,8 +43,8 @@
 			      sps->data_size);
 			return SPM_INVALID_PARAMETER;
 		}
-		int duration_sec = sps->data[0];
-		sp_sleep(duration_sec);
+		uint32_t duration_sec = sps->data[0];
+		sp_sleep(duration_sec * 1000);
 
 		/*
 		 * Write back to the communication buffer to acknowledge the