staging: rtl8723bs: Remove function 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().
Change references to _rtw_alloc_network() to refer to
rtw_alloc_network().
Issue first noticed while using Coccinelle and ret.cocci.

Signed-off-by: Nishka Dasgupta <nishka.dasgupta@yahoo.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>