sysinfo.h: Add re-inclusion guard

Add #ifndef __SYSINFO_H__ ... #endif to prevent re-inclusion of this
file.

Signed-off-by: Tom Rini <trini@konsulko.com>

include/sysinfo.h

@@ -4,6 +4,9 @@
  * Mario Six,  Guntermann & Drunck GmbH, mario.six@gdsys.cc
  */
 
+#ifndef __SYSINFO_H__
+#define __SYSINFO_H__
+
 struct udevice;
 
 /*
@@ -228,3 +231,4 @@ static inline int sysinfo_get_fit_loadable(struct udevice *dev, int index,
 }
 
 #endif
+#endif