staging: rtl8723bs: Remove wrapper functions and change function names

Drop wrappers rtw_init_cmd_priv and rtw_init_evt_priv and remove their
function declarations, as their only purpose is to call other functions.
Change function names from _rtw_init_cmd_priv to
rtw_init_cmd_priv, and _rtw_init_evt_priv to rtw_init_evt_priv in
function definitions and function declarations. Also, remove externs in
function declarations rtw_init_cmd_priv and rtw_init_evt_priv, to
maintain Linux kernel coding style.

Signed-off-by: Madhumitha Prabakaran <madhumithabiw@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>