Fix implicit declaration of function 'prctl' in installd.

(cherry picked from commit ec535c5ba515f58791aa5044ba116d35a10a188e)

Change-Id: I3da977d85ce544b23ff00934fdbd201d683e9210
diff --git a/cmds/installd/installd.c b/cmds/installd/installd.c
index 3be72a4..62579b9 100644
--- a/cmds/installd/installd.c
+++ b/cmds/installd/installd.c
@@ -15,7 +15,7 @@
 */
 
 #include <sys/capability.h>
-#include <linux/prctl.h>
+#include <sys/prctl.h>
 #include <selinux/android.h>
 #include <selinux/avc.h>