vrend_decode_clear: fix undefined-behavior for mis-aligned cast

Use memcpy to fix the UBSAN error.

Reviewed-by: Elie Tournier <elie.tournier@collabora.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

src/vrend_decode.c

@@ -199,7 +199,8 @@ static int vrend_decode_clear(struct vrend_decode_ctx *ctx, int length)
    buffers = get_buf_entry(ctx, VIRGL_OBJ_CLEAR_BUFFERS);
    for (i = 0; i < 4; i++)
       color.ui[i] = get_buf_entry(ctx, VIRGL_OBJ_CLEAR_COLOR_0 + i);
-   depth = *(double *)(uint64_t *)get_buf_ptr(ctx, VIRGL_OBJ_CLEAR_DEPTH_0);
+   double *depth_ptr = (double *)(uint64_t *)get_buf_ptr(ctx, VIRGL_OBJ_CLEAR_DEPTH_0);
+   memcpy(&depth, depth_ptr, sizeof(double));
    stencil = get_buf_entry(ctx, VIRGL_OBJ_CLEAR_STENCIL);
 
    vrend_clear(ctx->grctx, buffers, &color, depth, stencil);