common: Add includes for used types

common.h makes use of va_list, stdbool and stdint types, so lets include
them to make the header self-contained.

Change-Id: I3a62bfd80d4f138edee749587330c498e7232f38
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
diff --git a/common.h b/common.h
index 14fdfe9..55b7b1e 100644
--- a/common.h
+++ b/common.h
@@ -17,6 +17,10 @@
 #ifndef COMMON_H
 #define COMMON_H
 
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+
 #ifndef PREFIX
 #define PREFIX ""
 #endif