usb: xhci: Remove incorrect comments for struct xhci_container_ctx

There is no member called 'dma' in struct xhci_container_ctx. Remove
the comments that mentions it.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Stefan Roese <sr@denx.de>
Tested-by: Stefan Roese <sr@denx.de>
1 file changed