tests/*version: add missing string.h header

Prodives memset() and strlen(), used in tests/setversion
tests/getversion respectively.

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
diff --git a/tests/getversion.c b/tests/getversion.c
index 711d376..53d1d35 100644
--- a/tests/getversion.c
+++ b/tests/getversion.c
@@ -25,6 +25,7 @@
  *
  */
 
+#include <string.h>
 #include "drmtest.h"
 
 /**
diff --git a/tests/setversion.c b/tests/setversion.c
index 3aaf7cc..5a5d01c 100644
--- a/tests/setversion.c
+++ b/tests/setversion.c
@@ -26,6 +26,7 @@
  */
 
 #include <limits.h>
+#include <string.h>
 #include "drmtest.h"
 
 /**