staging: r8188eu: rtw_free_xmitframe_queue needs no spinlock

There's no need for a spinlock in rtw_free_xmitframe_queue.

This function is called only from rtw_free_stainfo. rtw_free_stainfo holds
pxmitpriv->lock during all rtw_free_xmitframe_queue calls.

Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20230130195303.138941-2-martin@kaiser.cx


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>