staging: rtl8188eu: Replace function rtw_alloc_network()

staging: rtl8188eu: Replace function rtw_alloc_network()

Change external call site of _rtw_alloc_network to rtw_alloc_network.
Remove function rtw_alloc_network as all it does is call
_rtw_alloc_network.
Rename _rtw_alloc_network to rtw_alloc_network to maintain compatibility
with call sites. Keep its type as non-static (even though the old
rtw_alloc_network was static) as this functionality is used in other
files as well.
Issue found with Coccinelle.

Signed-off-by: Nishka Dasgupta <nishkadg.linux@gmail.com>
Link: https://lore.kernel.org/r/20190712071746.2474-6-nishkadg.linux@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>