win-capture: avoid multiple definitions of data

At link time unless they are defined static they will conflict

plugins/win-capture/graphics-hook/d3d10-capture.cpp

@@ -54,7 +54,7 @@ struct d3d10_data {
 	};
 };
 
-struct d3d10_data data = {};
+static struct d3d10_data data = {};
 
 void d3d10_free(void)
 {

plugins/win-capture/graphics-hook/d3d11-capture.cpp

@@ -55,7 +55,7 @@ struct d3d11_data {
 	};
 };
 
-struct d3d11_data data = {};
+static struct d3d11_data data = {};
 
 void d3d11_free(void)
 {