staging: r8188eu: merge two rtw_free_network_nolock functions

Remove the _rtw_free_network_nolock function and merge it into
rtw_free_network_nolock, which is its only caller.

Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com> # Edimax N150
Link: https://lore.kernel.org/r/20221106124901.720785-9-martin@kaiser.cx


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