vrend: fix memory leak in int blit context

The 'blit_ctx->initialised' is not setted to true.
Every time init blit context, it will create a new
'blit_ctx->gl_context' thus causing a memory leak.
This patch avoid this.

Signed-off-by: Li Qiang <liq3ea@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

src/vrend_blitter.c

@@ -361,6 +361,7 @@ static void vrend_renderer_init_blit_ctx(struct vrend_blitter_ctx *blit_ctx)
       return;
    }
 
+   blit_ctx->initialised = true;
    ctx_params.shared = true;
    ctx_params.major_ver = VREND_GL_VER_MAJOR;
    ctx_params.minor_ver = VREND_GL_VER_MINOR;