mesa: include mtypes.h in varray.h

We actually use some of the types from mtypes.h so include it directly
instead of relying on indirectly including it via bufferobj.h

Reviewed-by: Charmaine Lee <charmainel@vmware.com>

src/mesa/main/varray.h

@@ -28,11 +28,9 @@
 #define VARRAY_H
 
 
-#include "glheader.h"
+#include "mtypes.h"
 #include "bufferobj.h"
 
-struct gl_vertex_array;
-struct gl_context;
 
 /**
  * Returns a pointer to the vertex attribute data in a client array,