sim: or1k: fix include ordering with sim-main.h

Make sure config.h is included before C library headers otherwise the
later libiberty.h include gets confused about asprintf state leading
to warnings like:
common/sim-utils.c:330:9:
	warning: implicit declaration of function 'vasprintf';
	did you mean 'xvasprintf'? [-Wimplicit-function-declaration]

sim/or1k/ChangeLog

@@ -1,3 +1,7 @@
+2021-01-11  Mike Frysinger  <vapier@gentoo.org>
+
+	* sim-main.h: Include config.h.
+
 2021-01-11  Mike Frysinger  <vapier@gentoo.org>
 
 	* config.in, configure: Regenerate.

sim/or1k/sim-main.h

@@ -21,6 +21,8 @@
 
 #define WITH_SCACHE_PBB 1
 
+#include "config.h"
+
 #include "ansidecl.h"
 #include "or1k-desc.h"
 #include "sim-basics.h"