compiler: remove now unused copy_shader_info() declaration

Left over from 4ac66861

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>

src/compiler/shader_info.h

@@ -141,13 +141,6 @@ typedef struct shader_info {
    };
 } shader_info;
 
-struct gl_shader_program;
-struct gl_linked_shader;
-
-void
-copy_shader_info(const struct gl_shader_program *shader_prog,
-                 struct gl_linked_shader *sh);
-
 #ifdef __cplusplus
 }
 #endif